JP2015147398A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently supply a reaction liquid for forming an image together with a recording liquid in a stable state.SOLUTION: An inkjet printer 100 is provided for transferring a recording liquid by contact between an intermediate transfer roller 37 and transfer paper S, by forming an image on the intermediate transfer roller 37, by discharging the recording liquid (ink) from heads 61Y-61BK, and comprises a coating device 20 for coating a reaction liquid Lq for reacting by contacting-mixing with the recording liquid on the intermediate transfer roller 37 and a reaction liquid supply device 30 having a plurality of supply passages and supplying the reaction liquid Lq to the coating device 20, and the reaction liquid supply device 30 can independently switch supply-stopping of the reaction liquid Lq with every plural supply passages.

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that transfers an image formed on an intermediate transfer member to a recording medium.

  2. Description of the Related Art Conventionally, an image forming apparatus such as an ink jet printer that includes a head that discharges a recording liquid such as ink from a plurality of nozzles and performs ink jet recording is known.

  A general ink jet recording apparatus performs recording by directly ejecting a recording liquid onto a recording medium. Since the recording medium is mainly plain paper, the image quality deteriorates due to various factors such as a decrease in density and setback as the recording liquid bleeds along the fibers of the paper or penetrates into the paper. In addition, since the image state varies depending on the paper type, not limited to plain paper, it is usually necessary to adjust the density and hue for each paper type. In order to address these problems, an intermediate transfer member is provided, an image is formed once on the intermediate transfer member using a reaction solution or a curing agent, and then transferred to a recording medium to obtain a high-quality image. Methods have been studied (see, for example, Patent Documents 1 to 3).

  Here, when the reaction liquid or the curing agent is attached to the intermediate transfer member, it is generally attached to the entire surface of the intermediate transfer member so as to be compatible with various papers and images. When the recording medium used is small relative to the maximum size, a part of the intermediate transfer member becomes an area that does not come into contact with the recording medium, and the reaction liquid adhering to this part is not only wasted, but also transferred. At this time, the recording medium also adheres to a pressure member that presses the recording medium against the intermediate transfer member, which causes the back surface of the recording medium and the inside of the apparatus to be contaminated.

  For this reason, for example, in Patent Document 1, the supply portion of the fountain head that supplies the coating liquid is limited in accordance with the paper width, and the liquid is supplied only to a necessary portion. However, in this method, it is necessary to adjust the pressure and feed amount during supply in accordance with the change in the supply width of the liquid, and the pressure distribution within the supply width must always be constant. In addition, when the pressure is excessive, the coating liquid leaks from the restricting portion, and when the pressure is insufficient, the amount of coating liquid deposited may be non-uniform, so that complicated and delicate control is required.

  Further, in Patent Documents 2 and 3, the paint once adhered is limited to a desired range by scraping. However, since it is once exposed to the atmosphere in a thin film state and has been altered, it can be reused as it is. The scraped paint is discarded and becomes a high cost factor.

  The present invention provides an image formation in which a recording liquid is ejected from a recording liquid ejection head to form an image on an intermediate transfer member, and the image is transferred to the recording medium by contact between the intermediate transfer member and the recording medium. An apparatus for applying a reaction liquid that reacts by contacting and mixing with the recording liquid onto the intermediate transfer member; a plurality of supply paths; and the application via the plurality of supply paths. A reaction solution supply device for supplying the reaction solution to the device, and the reaction solution supply device is an image forming apparatus capable of independently switching supply / stop of the reaction solution for each of the plurality of supply paths. is there.

  According to the image forming apparatus of the present invention, since the reaction liquid can be supplied only to a necessary area, the efficiency is high.

1 is a diagram schematically showing the configuration of an ink jet printer according to a first embodiment of the present invention. It is a perspective view which shows the coating device which the inkjet printer of FIG. 1 has. It is a side view of the coating device of FIG. 4A is an exploded view of the switching device included in the reaction liquid supply device, and FIGS. 4B to 4D are diagrams for explaining the operation of the switching device. FIG. 5A is a diagram illustrating an example of the arrangement of the nozzles of the reaction liquid supply apparatus, and FIG. 5B is a diagram illustrating another example of the arrangement of the nozzles of the reaction liquid supply apparatus. It is a figure which shows the control flow of a coating device. It is a perspective view which shows the reaction liquid supply apparatus which concerns on 2nd Embodiment. It is a side view of the rotor drive device which the reaction liquid supply apparatus of FIG. 7 has. FIG. 9A and FIG. 9B are diagrams illustrating a switching device included in the reaction liquid supply apparatus according to the third embodiment. FIG. 10A is a diagram showing a first modification of the nozzle front end view of the reaction liquid supply apparatus, and FIG. 10B is a diagram showing a second modification of the nozzle front end view of the reaction liquid supply apparatus. is there.

<< First Embodiment >>
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 schematically shows the configuration of an inkjet printer 100 as an image forming apparatus according to the first embodiment of the present invention. As will be described later, the ink jet printer 100 of the present embodiment includes an intermediate transfer roller 37 (intermediate transfer drum). In the following description, for convenience, the direction parallel to the rotation axis of the intermediate transfer roller 37 is the X axis direction, the direction orthogonal to the X axis is the Y axis direction, and the direction orthogonal to the XY plane (horizontal plane) (vertical direction) is the Z axis. The direction will be described as appropriate.

  The inkjet printer 100 can perform full color image formation. The ink jet printer 100 performs an image forming process based on an image signal (image data) corresponding to image information received from the outside. The ink jet printer 100 according to the present embodiment uses an OHP sheet, thick paper such as a card and postcard, and an envelope as a sheet-like recording medium in addition to plain paper generally used for copying. It is possible to form. In this embodiment, a single-sided image forming apparatus capable of forming an image on one side of a transfer sheet S as a recording sheet as a recording medium will be described. The present invention can also be suitably applied to an image forming apparatus.

  The inkjet printer 100 includes heads 61Y, 61M, which are ink heads that discharge recording liquids (inks) of the corresponding colors that can form images corresponding to the respective colors separated into yellow, magenta, cyan, and black. 61C, 61BK. In the present embodiment, all of the recording liquids (inks) ejected from the heads 61Y, 61M, 61C, 61BK are aqueous recording liquids containing a colorant. Each head 61Y, 61M, 61C, 61BK has a piezo-type movable actuator, for example, which is driven according to an image signal (image data), and is transferred via an intermediate transfer roller 37 (not shown). A recording liquid is applied to S to form an image.

  The heads 61Y, 61M, 61C, and 61BK are disposed at positions facing the outer peripheral surface of the intermediate transfer roller 37 that is disposed at a substantially central portion of the main body of the inkjet printer 100. The heads 61Y, 61M, 61C, 61BK are arranged in this order from the upstream side in the A1 direction, which is the movement direction of the intermediate transfer roller 37, which is the clockwise direction in FIG. In the drawing, Y, M, C, and BK added after the numerals of the reference numerals indicate members for yellow, magenta, cyan, and black. Although not shown in FIG. 1 because it is overlapped in the depth direction of the paper surface, the heads 61Y to 61BK are line heads provided in a form in which a plurality of heads 61Y to 61BK are arranged in a direction perpendicular to the paper surface of FIG.

  The intermediate transfer roller 37 is rotated in the A1 direction, and the yellow, magenta, cyan, and black recording liquids are sequentially superimposed from the heads 61Y to 61BK in a region facing the heads 61Y to 61BK. Discharged and applied. Thereby, the intermediate transfer roller 37 functions as a recording medium on which an image as a primary image is formed on a primary image forming surface as a surface thereof. Thus, the ink jet printer 100 has a tandem structure in which the heads 61Y to 61BK are opposed to the intermediate transfer roller 37 and are arranged in parallel in the A1 direction.

  The recording liquid is discharged to the intermediate transfer roller 37 by the heads 61Y to 61BK, that is, the recording liquid is applied at different timings from the upstream side toward the downstream side in the A1 direction. As a result, the image areas of yellow, magenta, cyan, and black are overlapped at the same position on the intermediate transfer roller 37 to form an image.

  The ink jet printer 100 is also not shown in FIG. 1, but includes a paper transport unit that transports the transfer paper S in the + Y direction (see the black arrow in the figure) as the intermediate transfer roller 37 rotates in the A1 direction. And a sheet discharge table on which a large number of image-formed (in other words, printed) transfer sheets S conveyed by the sheet conveyance unit can be stacked.

  The ink jet printer 100 also has a cleaning device 40. The cleaning device 40 is provided so as to be able to come into contact with and separate from the intermediate transfer roller 37 and includes a cleaning blade having wear resistance. From the intermediate transfer roller 37 after the ink has been transferred to the transfer paper S, the cleaning device 40 is placed on That is, the recording liquid remaining on the primary image forming surface is removed and cleaned (reset). This reset operation may be always performed or may be performed at a specific timing by control.

  The ink jet printer 100 is also arranged to face the intermediate transfer roller 37 at a position upstream of the heads 61Y to 61BK in the A1 direction (before the heads 61Y to 61BK), and has a predetermined composition and a predetermined state of reaction. An application device 20 that applies the liquid Lq (application agent) to the intermediate transfer roller 37 is provided. The configuration of the coating device 20 will be described in detail later.

  The ink jet printer 100 also has a control unit (not shown) as a control means including a CPU, a memory, etc. (not shown) that controls the overall operation of the ink jet printer 100. The ink ejection device including the heads 61Y to 61BK, the transport unit (not shown), the cleaning device 40, and the control board (not shown) of each head provided in the control unit constitute a printing unit. .

  The ink jet printer 100 also has a transfer roller 38. The transfer roller 38 sandwiches the transfer sheet S with the intermediate transfer roller 37, and transfers the image on the intermediate transfer roller 37 while being driven to rotate in the direction of the arrow A2 while the transfer sheet S is sandwiched. Transfer to paper S. As is apparent from the above description, the ink jet printer 100 is an indirect image forming apparatus that indirectly forms an image on the transfer paper S using the intermediate transfer roller 37.

  The coating device 20 is a device for coating the predetermined reaction liquid Lq on the outer peripheral surface of the intermediate transfer roller 37 with a small coating unevenness and a small film thickness. The application device 20 includes an intermediate transfer roller on the downstream side of the position where the cleaning device 40 cleans the intermediate transfer roller 37 in the A1 direction and on the upstream side of the position where the heads 61Y to 61BK discharge the recording liquid to the intermediate transfer roller 37. 37. The coating device 20 applies the reaction liquid Lq to the intermediate transfer roller 37 at this position.

  Here, the reaction liquid Lq applied to the intermediate transfer roller 37 by the coating device 20 will be briefly described. The base of the reaction liquid Lq is a low polarity solvent that is incompatible with water, that is, phase-separated at room temperature. The reaction liquid Lq is obtained by emulsifying water containing a water-soluble polymer and a nonpolar solvent incompatible with the water using a surfactant. That is, the reaction liquid Lq has a form in which a water phase containing a water-soluble polymer is dispersed into a W / O emulsion in a state where the water-soluble polymer is dissolved in a nonpolar solvent using a surfactant. It has become. In the inkjet printer 100, an aqueous recording liquid is used as the recording liquid (ink), and the recording liquid is discharged from the heads 61Y, 61M, 61C, 61BK, and the discharged recording liquid and the reaction liquid Lq are brought into contact with each other and mixed. . And by this contact etc., a reaction liquid carries out phase inversion to O / W emulsion, and exhibits a thickening effect | action. The water-soluble polymer in the reaction liquid Lq causes the colored components in the recording liquid to thicken and aggregate, and when the recording liquid is transferred to the transfer paper S, the colored components in the recording liquid bleed into the transfer paper S. It has a function to prevent or suppress.

  The coating device 20 includes a doctor blade 22, a gravure roller 24, a coating roller 26, a reaction liquid supply device 30, a control device 28 that controls each of the above elements, and the like.

  The doctor blade 22 is a squeegee member formed in a plate shape, and one end (tip) portion is in contact with the outer peripheral surface of the gravure roller 24. The reaction liquid Lq is stored between the doctor blade 22 and the outer peripheral surface of the gravure roller 24. The doctor blade 22 is biased in a direction in which the tip portion presses the outer peripheral surface of the gravure roller 24, and has a function of adjusting the amount of the reaction liquid Lq adhering to the outer peripheral surface of the gravure roller 24. The urging force for urging the doctor blade 22 may be the elastic force of the doctor blade 22 itself, or may be applied from the outside using an urging device such as a spring.

  On the outer peripheral surface of the gravure roller 24, a large number of precise cells carved in a pyramid shape or a lattice shape (pyramidal frustum shape) are formed with a predetermined density (see FIG. 2). The length of the gravure roller 24 in the axial direction is set to be equal to or longer than the length of the intermediate transfer roller 37 in the axial direction. The arrangement form of the cells on the surface of the gravure roller 24 is not particularly limited, but a form in which the cells are arranged along an oblique line that is not orthogonal to the rotation direction (arrow A3 direction in FIG. 1) is preferable. The cell shape, depth, cell volume, density, and the like are appropriately selected according to the amount of liquid to be applied (the thickness of the liquid film after application). The gravure roller 24 is also called an anilox roller or a precision roller.

  The application roller 26 is arranged on the downstream side of the cleaning device 40 and the upstream side of the head 61Y with respect to the rotation direction (A1 direction) of the intermediate transfer roller 37, and is in contact with the intermediate transfer roller 37 at this position. By rotating in the A4 direction which is the opposite direction to the roller 37, it functions as a reaction liquid application member for applying the reaction liquid Lq. The application roller 26 and the intermediate transfer roller 37 are set so that the rotational axis is substantially parallel (parallel to the X axis) and the length in the axial direction is substantially the same.

  In the coating apparatus 20, when the gravure roller 24 rotates in the A3 direction (the same rotation direction as the intermediate transfer roller 37), among the reaction liquid Lq stored between the gravure roller 24 and the doctor blade 22, between adjacent cells. Only the reaction liquid Lq held in the formed groove (not shown) passes between the tip of the doctor blade 22 and the outer peripheral surface of the gravure roller 24. The outer peripheral surface of the gravure roller 24 is partially in contact with the outer peripheral surface of the application roller 26, and the reaction liquid Lq attached to the outer peripheral surface of the gravure roller 24 is transferred to the outer peripheral surface of the application roller 26 at the contact portion.

  As shown in FIG. 2, the reaction liquid supply device 30 includes a plurality of tubes 32 including a discharge nozzle for the reaction liquid Lq, a rotor 34 for discharging the reaction liquid Lq from each of the plurality of tubes 32, and a plurality of tubes 32. A switching device 36 for switching on / off of discharge of the reaction liquid Lq from a part of the apparatus, a reaction liquid tank (not shown), and the like are provided. The plurality of tubes 32 and the rotor 34 constitute a so-called tubing pump (tube pump) that conveys the reaction liquid Lq while being blocked from the outside air.

  Each of the plurality of tubes 32 extends substantially parallel to the Y axis and is arranged at a predetermined interval in the X axis direction. The number of the tubes 32 is not particularly limited, but is arranged so that the reaction liquid Lq can be supplied in a range equivalent to at least the width direction dimension of the maximum paper that can be printed in this embodiment. In FIG. 2, among the plurality of tubes 32, only a few tubes 32 arranged in the vicinity of both ends in the Y-axis direction are shown, and the tubes 32 near the center are not shown.

  The distal ends of the plurality of tubes 32 are arranged above the vicinity of the other end of the doctor blade 22 and function as discharge nozzles. The reaction liquid Lq discharged from the tip of the tube 32 is dropped on the doctor blade 22 and supplied to the gravure roller 24 via the doctor blade 22. The other end of each of the plurality of tubes 32 is connected to a reaction liquid tank (not shown). The tube 32 is formed of an elastic material, for example, a rubber-based or synthetic resin-based material.

  The rotor 34 includes a pair of disk members 34a, a plurality of (for example, six in this embodiment) shafts 34b provided between the pair of disk members 34a, and a drive connected to the outer surface of the disk member 34a. The shaft 34c, a driving device (not shown), and the like are included. The rotor 34 is driven to rotate about an axis parallel to the X axis by a drive shaft 34c by a drive device (not shown). The shaft 34b is made of a member having a circular YZ section extending substantially parallel to the X axis, and is attached to the disk member 34a so as to be rotatable around the X axis. The plurality of shafts 34b are arranged at substantially equal intervals around the X axis. As shown in FIG. 3, in the reaction liquid supply device 30, when the rotor 34 rotates, the plurality of tubes 32 are crushed (crushed) into one or two of the plurality of shafts 34 b, thereby the tubes 32. The reaction liquid Lq inside is discharged from the tip of the tube 32.

  As shown in FIG. 4A, the switching device 36 includes a switching roller 36a and a plurality of tube guides 36b. The number of tube guides 36b matches the number of tubes 32 (see FIG. 2), and the tube guides 36b and the tubes 32 are in a one-to-one relationship. In FIG. 4A, for example, the case where there are 10 tube guides 36b is shown as an example, but as described above, the number of tubes 32 is not particularly limited, and therefore the tube guides corresponding thereto. The number of 36b is not particularly limited, and can be appropriately changed according to the number of tubes 32. The switching roller 36a is formed of a cylindrical member extending in a direction substantially parallel to the X axis. The switching roller 36a is rotatable around the X axis at a predetermined angle and is movable in a vertical stroke (Z axis) with a predetermined stroke. The rotation operation and vertical operation of the switching roller 36a are controlled by the control device 28 (see FIG. 1).

  On the outer peripheral surface of the switching roller 36a, three regions (region I, region II, region III) are formed with substantially equal areas in the circumferential (around the X axis) direction. In area I, recesses 36c (notches) are formed in the vicinity of both ends of the switching roller 36a. The dimension in the width direction (X-axis direction) of the recess 36c is approximately twice the dimension in the width direction (X-axis direction) of the tube guide 36b. In the region II, recesses 36d (notches) are formed in the vicinity of both ends of the switching roller 36a. The dimension in the width direction (X-axis direction) of the recess 36d is substantially half of the dimension in the width direction (X-axis direction) of the recess 36c (that is, substantially the same as the dimension in the width direction of one tube guide 36b). The concave portion 36c and the concave portion 36d are formed in a stepped manner and have the same depth. On the other hand, in the region III, the concave portions corresponding to the concave portions 36c and 36d are not formed, and the height positions thereof are uniform.

  The plurality of tube guides 36b are arranged at predetermined intervals in the X-axis direction. Each of the plurality of tube guides 36b is movable independently of each other with a predetermined stroke in the vertical (Z-axis) direction. The tube guide 36b is formed of a substantially rectangular parallelepiped member. However, the upper surface of the tube guide 36b is a curved surface curved with a curvature corresponding to the outer peripheral surface of the disk member 34a of the rotor 34. Further, the lower surface of the tube guide 36b is a curved surface curved with a curvature corresponding to the outer peripheral surface of the switching roller 36a.

  The control device 28 (see FIG. 1) rotates the switching roller 36a around the X axis in a state in which each of the plurality of tube guides 36b and the switching roller 36a are separated from each other, of the outer peripheral surface of the switching roller 36a. A region facing the lower surface of each of the plurality of 36b can be selected. For example, the lower surface of each of the plurality of tube guides 36b and the region III (region where no recess is formed) of the outer peripheral surface of the switching roller 36a are opposed to each other, and the switching roller 36a is raised in this state to switch the switching roller 36a. When the tube guide 36b is brought into contact with each other, as shown in FIG. 4B, the heights of all the tube guides 36b coincide with each other. In the state shown in FIG. 4B, all the tube guides 36b can contact the corresponding tube 32 (see FIG. 2).

  Further, the switching roller 36a and the tube guide 36b are brought into contact with each other in a state where the lower surface of each of the plurality of tube guides 36b and the region II (the region where the recess 36d is formed) of the outer peripheral surface of the switching roller 36a face each other. As shown in FIG. 4C, the height position of the outermost pair of tube guides 36b is lower than the other tube guides 36b. In the state shown in FIG. 4C, among the plurality of tubes 32 (see FIG. 2), the outermost pair of tubes 32 and the corresponding pair of tube guides 36b are separated from each other, and other tubes 32 and the tube guide 36b corresponding to these can be contacted.

  Similarly, when the switching roller 36a and the tube guide 36b are brought into contact with each other in a state where the lower surface of each of the plurality of 36b and the region I (the region where the recess 36c is formed) of the outer peripheral surface of the switching roller 36a face each other. As shown in FIG. 4D, the total height of the four tube guides 36b, two on the + X side and two on the -X side, is lower than the other tube guides 36b. . In the state shown in FIG. 4D, among the plurality of tubes 32 (see FIG. 2), a total of four tubes 32, two on the + X side and two on the −X side, correspond to these. The four tube guides 36b are separated from each other, and the other tubes 32 and the corresponding tube guides 36b can be brought into contact with each other.

  Here, since the tube pump is configured to discharge the reaction liquid Lq when the tube 32 is squeezed by the rotor 34, the rotor 34 rotates when the tube guide 36b and the tube 32 are separated from each other. However, the desired amount of the reaction liquid Lq is not discharged from the tube 32. Therefore, even if the rotor 34 is always rotating, the reaction liquid Lq is not discharged from the tube 32 that is separated from the tube guide 36b. Thereby, the discharge / non-discharge (supply / stop) of the reaction liquid Lq from the arbitrary tube 32 can be switched according to the position of the tube guide 36b, in other words, the discharge range of the reaction liquid Lq can be controlled. Specifically, in the case illustrated in FIG. 4B, the reaction liquid Lq is discharged from all the tubes 32. 4C, the reaction liquid Lq is not discharged from the outermost pair of tubes 32, and the reaction liquid Lq is discharged from the remaining tubes 32. In addition, in the case shown in FIG. 4C, the reaction solution Lq is not discharged from the total of four tubes 32, that is, two on the + X side and two on the −X side, and from the remaining tubes 32. The reaction liquid Lq is discharged.

  Here, the inkjet printer 100 (see FIG. 1) as in the present embodiment can print on a plurality of different sizes of paper. A plurality of sheets having different sizes are accommodated in dedicated cassettes (not shown), respectively, and conveyed to a transfer position (between the intermediate transfer roller 37 and the transfer roller 38) by an independent paper feeder. In the inkjet printer 100, there are models having different positions in the paper width direction (direction orthogonal to the paper transport direction) in the cassette. More specifically, as shown in FIG. 5A, A4, B4, and A3 size sheets are arranged so that the center portions in the width direction coincide with each other, or in FIG. As shown, there are models that are arranged so that one end in the width direction thereof matches. Note that the size of paper that can be printed by the inkjet printer 100 is not limited to the size shown in FIGS. 5A and 5B, and can be changed as appropriate. Further, the arrangement of sheets in the cassette is not limited to the example shown in FIGS. 5A and 5B, and can be changed as appropriate.

  Accordingly, when the ink jet printer is of the type shown in FIG. 5B, correspondingly, as shown in FIG. 4A, recesses 36c and 36d are formed in the vicinity of both ends in the longitudinal direction. It is preferable to use the switching roller 36a. In the first embodiment, the switching device 36 corresponding to the type shown in FIG. 5A is described. However, when the ink jet printer is the type shown in FIG. Correspondingly, a switching roller (not shown) in which a recess is formed only in the vicinity of one end in the longitudinal direction may be used. 2 and 3, the recess 36c is not shown. However, as described above, the recess 36c may be appropriately formed according to the layout of the paper.

  Next, an example of a control flow performed by the control device 28 of the coating apparatus 20 will be described with reference to FIG. In the inkjet printer 100, when the user inputs the start of printing, the image data related to the printing is transmitted from the host control device to the control device 28, for example, according to the input (start). When receiving the image data in step S1, the control device 28 proceeds to step S2, performs analysis of the image data (here, the width of the image, that is, the width direction dimension of the transfer paper S used for printing), and proceeds to step S3. . In step S <b> 3, the control device 28 determines the application width of the reaction liquid Lq according to the width direction dimension of the transfer paper S. Specifically, in this step S3, as shown in FIG. 5A or FIG. 5B, it is determined which tube 32 of the plurality of tubes 32 is supplied with the reaction liquid Lq from the supply port. To do. The control device 28 controls the switching device 36 based on the result (application width) in step S3 so as to be in any one of the modes shown in FIGS. 4 (b) to 4 (d). Then, it progresses to step S4 and the tubing pump (rotor 34) is controlled and the reaction liquid Lq is dripped on the doctor blade 22. FIG. Note that the upper control device may control the coating device 20 in an integrated manner without providing the independent control device 28 in the coating device 20.

  Here, the reaction liquid Lq has a property of reacting with moisture in the atmosphere, ultraviolet light in a normal environment, or the like, and is dried by being exposed to the atmosphere. Because these properties are formed as a thin film on the coating roller 26 of the coating apparatus 20, the area of exposure to the atmosphere per unit volume increases, and the reaction is accelerated. In addition, there is an influence such as entrapment of dust and dust without forming a thin film.

  On the other hand, the reaction liquid supply device 30 included in the coating apparatus 20 according to the first embodiment described above feeds the reaction liquid Lq in a sealed manner through the tube 32 and supplies the minimum necessary amount. Therefore, the reaction of the reaction liquid Lq with respect to moisture, ultraviolet light, and the like can be suppressed without exposing the reaction liquid Lq to the atmosphere. Moreover, when changing the whole supply amount at the time of supplying the reaction liquid Lq to the gravure roller 24, it is desirable that the supply amount per unit volume does not change. In contrast, the reaction liquid supply device 30 of the present embodiment is provided with a plurality of tubes 32 (flow paths) for supplying the reaction liquid Lq, and the supply of the reaction liquid Lq from each tube 32 is independently controlled. A necessary amount of the reaction liquid Lq can be easily supplied only to a necessary portion while maintaining a constant supply amount per unit volume.

  Further, according to the reaction liquid supply device 30 of the present embodiment, since the reaction liquid Lq is not applied in a range where it is not necessary to apply the reaction liquid Lq, the useless reaction liquid Lq is not generated, so that the efficiency is high. Further, contamination of the transfer roller 38 and the back surface of the transfer paper S can be suppressed. Further, according to the reaction liquid supply device 30 of the present embodiment, the application range of the reaction liquid Lq can be switched only by moving the tube guide 36b up and down, so the apparatus is compact and easy to control.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIGS. The inkjet printer according to the second embodiment described below is substantially the same as that of the first embodiment except that the configuration of the reaction liquid supply device 70 is different. Therefore, only the differences will be described below. And about the element which has the same structure and function as the said 1st Embodiment, the code | symbol same as the said 1st Embodiment is attached | subjected and the description and illustration are abbreviate | omitted.

  In the first embodiment (see FIG. 2), the tube 32 and the tube guide 36b are separated so as not to discharge the reaction liquid Lq from the tube 32, whereas in the second embodiment, the tubing pump is The difference is that the tubes 32 that are provided independently to the plurality of tubes 32 and that do not discharge the reaction liquid Lq are selected by switching the operation of the tubing pump itself on and off.

  In the first embodiment, as shown in FIG. 2, one rotor 34 is provided for the plurality of tubes 32. On the other hand, in the second embodiment, as shown in FIG. 7, a plurality of rotors 72 are provided in a one-to-one relationship with the plurality of tubes 32.

  A plurality of shafts 73 are attached to the rotor 72 so as to be rotatable around the X axis. As shown in FIG. 8, the reaction liquid supply apparatus 70 is similar to the first embodiment in that the reaction liquid Lq is discharged from the tube 32 by squeezing the tube 32 using a plurality of shafts 73. It is. In the second embodiment, since it is not necessary to squeeze the tube 32 in cooperation with the rotor 72 and to separate the tube guide 74 from the tube 32, the position of the tube guide 74 differs from the first embodiment. Is fixed (does not move up and down).

  A plurality of teeth are formed on the outer periphery of the rotor 72, and the rotor 72 itself is a gear. Further, the reaction liquid supply device 70 has a cylindrical drive gear 76 for applying a rotational driving force to the rotor 72. The rotation operation of the drive gear 76 is controlled by the control device 28 (not shown in FIG. 7, refer to FIG. 1).

  Further, between each of the plurality of rotors 72 and the drive gear 76, a plurality of transmission gears 78 are interposed corresponding to each of the plurality of rotors 72. As shown in FIG. 8, the transmission gear 78 is separated from the drive gear 76 and a transmittable position (position indicated by a solid line in FIG. 8) that meshes with the teeth of the corresponding rotor 72 and the teeth of the drive gear 76. It is possible to move between the separated positions (positions indicated by broken lines in FIG. 8). The position of the transmission gear 78 is controlled by a control device (not shown in FIG. 7, see FIG. 1).

  In the reaction liquid supply device 70, as in the first embodiment, the tube 32 that does not discharge the reaction liquid Lq is selected according to the width-direction dimension of the paper to be printed, and the transmission gear corresponding to the tube 32 is selected. 78 is positioned in the spaced position. Regardless of the paper size, the position of the transmission gear 78 corresponding to the tube 32 that must always discharge the reaction liquid Lq may be fixed at a transmittable position.

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described with reference to FIGS. 9 (a) and 9 (b). The ink jet printer according to the third embodiment described below is substantially the same as the first embodiment except that the configuration of the reaction liquid supply device 80 is different. Therefore, only the differences will be described below. And about the element which has the same structure and function as the said 1st Embodiment, the code | symbol same as the said 1st Embodiment is attached | subjected and the description and illustration are abbreviate | omitted.

  As shown in FIG. 9A, the box-shaped cassette 42 that stores the transfer paper S has a lever 44 that regulates the end of the transfer paper S stored in the cassette 42. The lever 44 is movable according to the size of the transfer paper S. A movable member 46 that can move according to the size of the transfer sheet S (in conjunction with the lever 44) is provided outside the cassette 42. Further, an overhang member 48 different from the above-described movable member 46 is fixed to the outside of the cassette 42.

  The reaction liquid supply device 80 of the third embodiment has a plurality of tube guides 82. The tube guide 82 functions in the same manner as the tube guide 36b (see FIG. 3) of the reaction liquid supply device 30 of the first embodiment, that is, in cooperation with the rotor 34 (see FIG. 3), the tube 32 (see FIG. 3). Has a function of squeezing. Note that the ink jet printer of this embodiment is a type in which transfer sheets S of different sizes are accommodated in corresponding cassettes 42 with their ends aligned as shown in FIG. 5B.

  Some of the plurality of tube guides 82 move up and down in conjunction with the operation of the lever 44, and this up and down movement causes the tube 32 (not shown in FIG. 9B, see FIG. 3 etc.). Separate or touch. The tube guide 82 that always contacts the tube 32 is fixed on a fixed overhang member 48. The mechanism for moving the tube guide 82 up and down according to the operation of the lever 44 is not particularly limited, and for example, a lever, an eccentric cam, an individual actuator, or the like can be used. Since the configuration of the rotor (not shown) for squeezing the tube 32 in cooperation with the tube guide 82 is the same as that of the first embodiment, description thereof will be omitted. According to the third embodiment, in addition to the same effects as those of the first embodiment, supply / stop of the reaction liquid Lq from the tube 32 can be switched without using the control device 28.

  Each of the first to third embodiments is an example to which the image forming apparatus according to the present invention is applied, and the configuration can be appropriately changed. For example, the shape of the tip (nozzle) of the tube 32 in each of the above embodiments may be, for example, a slit shape as shown in FIGS. 10 (a) and 10 (b).

  In the first embodiment, the configuration of the device for switching contact / separation between the switching roller 36a and the tube guide 36b can be changed as appropriate. For example, a lever, an eccentric cam, an individual actuator, or the like can be used. it can. In addition, the device used for driving the transmission gear 78 in the second embodiment is not particularly limited, and for example, a lever, an eccentric cam, a partially cut roller, an individual actuator, or the like can be used. In the third embodiment, a paper size detection sensor or the like may be provided in the cassette 42, and the tube guide 82 may be moved up and down in conjunction with the sensor.

  Moreover, in each said embodiment, supply of the reaction liquid Lq was performed via the tube pump, However, The kind of pump is not specifically limited. In each of the above embodiments, the supply / stop of the reaction liquid Lq is switched by operating / stopping the tube pump. However, the present invention is not limited to this, and may be switched by opening / closing a valve or the like.

  In each of the above embodiments, the intermediate transfer body to which the reaction liquid Lq is applied by the coating apparatus 20 has a roller (drum) shape, but is not limited thereto, and may be, for example, an endless belt.

  Further, the heads 61Y, 61M, 61C, 61BK are not limited to a method of discharging a liquid by applying a pressure by a piezoelectric element. For example, a method of discharging a liquid by boiling a liquid by a heating unit, an electrostatic attraction by a voltage applying unit Therefore, an ink jet head to which any method such as a method of discharging a liquid is applied can be used.

  In each of the above embodiments, the case where the image forming apparatus is a color printer has been described. However, the image forming apparatus is not limited to this, and may be a monochrome copying machine, a color copying machine, a facsimile apparatus, a plotter apparatus, or the like. Alternatively, a so-called MFP (Multi Function Printer) that combines these functions may be used.

  DESCRIPTION OF SYMBOLS 20 ... Coating apparatus, 24 ... Gravure roller, 26 ... Coating roller, 28 ... Control apparatus, 30 ... Reaction liquid supply apparatus, 32 ... Tube, 34 ... Rotor, 36 ... Switching apparatus, 100 ... Inkjet printer, Lq ... Reaction liquid, S: Transfer paper.

JP 05-031424 A Japanese Patent No. 5051887 JP 09-314010 A

Claims (7)

An image forming apparatus for discharging a recording liquid from a recording liquid discharging head to form an image on an intermediate transfer member, and transferring the image to the recording medium by contact between the intermediate transfer member and the recording medium. ,
A coating apparatus that coats the intermediate transfer member with a reaction liquid that reacts by contacting and mixing with the recording liquid;
A reaction liquid supply apparatus that has a plurality of supply paths and supplies the reaction liquid to the coating apparatus via the plurality of supply paths;
The reaction liquid supply apparatus is an image forming apparatus capable of independently switching supply / stop of the reaction liquid for each of the plurality of supply paths.   The image forming apparatus according to claim 1, further comprising a control device that switches supply / stop of the reaction liquid according to a size of the recording medium. The image is formed based on image data,
The image forming apparatus according to claim 1, further comprising a control device that switches supply / stop of the reaction liquid based on the image data. A movable member movable according to the size of the recording medium;
The image forming apparatus according to claim 1, further comprising: a switching mechanism that mechanically switches supply / stop of the reaction liquid via the supply path according to a position of the movable member.   The image forming apparatus according to claim 1, wherein the supply path supplies the reaction liquid in a state of being blocked from outside air. The supply path is formed by a tube having elasticity,
The image forming apparatus according to claim 1, wherein the reaction liquid supply device supplies the reaction liquid by a tubing pump including the tube.   The image forming apparatus according to claim 6, wherein the reaction liquid is stopped by partially disabling a function of the tubing pump used for supplying the reaction liquid to be stopped.

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