JP5821360B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus known as a printer, a facsimile, a copying machine, a plotter, or a complex machine in which some of these are combined.

  As one form of an image forming apparatus, a liquid discharge recording method using a recording head for discharging ink droplets is known. For example, there is an ink jet recording apparatus that forms an image by ejecting and dropping ink droplets toward a recording medium.

  In an image forming apparatus using such a liquid, an image is formed using a recording liquid such as ink, and it takes a certain amount of time for the recording liquid that has landed on the recording medium to dry. Until the recording liquid dries, the recording medium is waited in the apparatus and then discharged. When performing double-sided printing, first, after printing on one side, once the recording medium is discharged onto the discharge tray, this recording medium is sent again to the printing section, and the remaining side is printed and then discharged. It is trying to discharge to the tray.

  As an image forming apparatus according to the prior art closest to the present invention, an image forming apparatus having a plurality of printing units and one or more paper feeding units, and selecting and recording the printing unit and the paper feeding unit according to a printing signal Is known (for example, see Patent Document 1).

  Hereinafter, with reference to FIG. 11, the description described in paragraph 0089 of Patent Document 1 is cited as follows: “The paper fed from the paper feeding unit 1 is indicated by an arrow by the variable paper guide 2 a of the printing unit 2. It is conveyed in the M direction and supplied to the conveyance roller 2b, and after printing is performed by the recording head 2c, it is conveyed to the downstream side of printing through the conveyance roller 2d. The paper is transported in the direction of arrow N and supplied to the opening 3a of the printing unit 3 through the opening 2f, and is further transported in the direction of arrow O by the operation of the variable paper guide 3b. After the opposite surface is printed by the recording head 3d, it is conveyed in the direction of the arrow P through the conveyance roller 3f.After the opposite surface is completely printed, the paper is reversed. In the direction of arrow Q Is fed through the conveying rollers 3f, 3c, are conveyed in the arrow I direction by the operation of the variable paper guide 3g, the. Above operation is discharged from the opening 4, it is possible to double-sided printing. "There.

  In such a double-sided printing method, (i). After the first image is formed by the first image forming means (recording head 2c) arranged in the middle stage of the image forming apparatus shown in FIG. 11, the second image is installed in the upper stage of the image forming apparatus. (B) a transport path for transporting the recording medium to the image forming means (recording head 3d) via a reverse path indicated by arrows N and O; The second image forming means (recording head 3d) has a confluence portion where the second path image is formed and the conveyance path for sending it to the paper discharge portion joins.

When there is such a merging section, when continuous printing is performed, while the paper on which the second surface is printed is on the transport path (b), the first surface on the transport path (b). There unable to pump paper printed on the conveying path of the (b). For this reason, there arises a waiting state in which it is necessary to wait for the delivery of the paper on the transport path (b) until the paper is sent out from the transport path (b). This is because the conveyance path that prints the second surface and goes to the discharge portion and the conveyance path that finishes printing the first surface and that forms the image on the second surface overlap each other. Can be a factor that reduces the productivity of image formation.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which a waiting state for printing does not occur due to duplication of a conveyance path as in the prior art.

In order to achieve the object, the present invention has the following configuration.
(1): In the image forming apparatus of the first means of the present invention,
A plurality of image forming units that form an image by a recording head that discharges droplets toward the recording medium are arranged in parallel in the vertical direction, and a paper feeding unit that sends out the recording medium toward the image forming unit; and the discharge portion of the recording medium after image formation is discharged from the exits the sheet feeding unit through one image forming means in said plurality of image forming means, first leading to the discharge unit a delivery diameter path, the other one image in said first of said plurality of image forming means is branched from the branch portion provided between the said sheet feeder to said one image forming means of the conveying path Having a second transport path that passes through the forming means and joins at the merge section upstream of the branch section on the first transport path;
After the image is formed on the first surface of the recording medium by the other image forming unit, the image is formed on the second surface of the recording medium by the one image forming unit. in images forming device discharged to the sheet discharge unit to form images on both sides,
A treatment liquid applying device for applying a treatment liquid to one side of the recording medium on the first conveyance path and between the paper feeding unit and the one image forming unit; On the transport path, between the processing liquid coating apparatus and the one image forming means, and the merging section is on the first transport path, the paper feeding section and the processing liquid coating apparatus. Inverting means for changing the direction of the recording medium is provided on the second transport path on the downstream side of the other image forming means.
In this configuration, the second transport path including the other image forming unit including the image forming unit that prints the first surface is branched from the first transport path on the upstream side of the one image forming unit. In addition, since it merges with the first conveyance path upstream of the branch portion, the conveyance path that prints the second surface toward the discharge portion and the image on the second surface after the first surface printing is completed. Therefore, there is a situation in which a recording medium that has finished printing on the first side and waits for a recording medium that has finished printing on the second side does not overlap with the conveyance path toward the formation. I don't get it. Further, in the second transport path, a reversing unit is provided between the other image forming unit and the merging unit so that the processing liquid coating surface is matched with the side suitable for the processing liquid coating apparatus. As a result, the processing liquid can be applied to a printing surface suitable for a plurality of image forming means with a single processing liquid coating apparatus, and the number of processing liquid coating apparatuses installed can be minimized.
(2): of the present invention in an image forming apparatus of the second means, the conveyance path before Symbol downstream leaving the other one of the image forming means is branched from the path leading to said inverting means, said first A third conveyance path is formed on the conveyance path and joins between the one image forming unit and the paper discharge unit .
In this configuration, the sheet that has exited the other image forming unit can be guided to the paper discharge unit without being reversed by passing through the third transport path. Therefore, even in the one image forming unit, In addition, each of the other image forming units can independently form a single-sided image, and can perform single-sided printing by alternately using a plurality of image forming units to improve printing productivity. Can do.

In the present invention, after the second surface is printed, the conveyance path toward the discharge unit and the conveyance path toward the second surface image formation after finishing the printing on the first surface do not overlap. The print waiting state due to the overlap of the conveyance path cannot occur between the recording medium that has finished printing the first face and the recording medium that has finished printing the first face and is ready for image formation on the second face. The productivity of formation can be improved and the number of processing liquid coating apparatuses installed can be minimized .

1 is a diagram illustrating a configuration of an image forming apparatus according to Example 1. FIG. 2A and 2B are enlarged views of a merging portion between the second conveyance path and the first conveyance path in FIG. FIG. 6 is a diagram illustrating a case where paper is prioritized. FIG. 2 is an enlarged view of a branching portion from a first transport path to a second transport path at a position immediately after the processing liquid coating apparatus in FIG. 1, wherein (a) gives priority to a sheet that follows the first transport path; FIG. 7B is a diagram illustrating a case where priority is given to a route that travels to the loop-shaped second conveyance route. FIG. 2 is an enlarged view of a path from the manual feed tray to the image forming unit in FIG. 1, a path from the processing liquid coating apparatus to the image forming unit, and a joining portion, and (a) gives priority to the sheet from the processing liquid coating apparatus. In the case of sending to the forming unit, (b) shows a case of giving priority to the sheet from the manual feed tray and sending it to the image forming unit. FIG. 4 is a diagram illustrating a configuration of an image forming apparatus according to Example 2 in which a third path is added to the image forming apparatus of FIG. 1. FIG. 6 is a diagram illustrating an aspect according to Example 2 in which a single-sided image is formed for each image forming unit in the image forming apparatus of FIG. 5. FIGS. 5A and 5B show an example of switching the third path in the image forming apparatus of FIG. 5, and FIG. 5A is a diagram illustrating a mode in which a sheet is guided to a reverse path without using the third path, and FIG. It is a figure explaining the aspect using the path | route. 6 is a diagram illustrating an image forming apparatus according to Example 3. FIG. FIG. 9 is a diagram illustrating a configuration of an image forming apparatus according to Example 4 in which a third path is added in the image forming apparatus of FIG. 8. 9A and 9B show an example of switching the third path. FIG. 9A is a diagram illustrating a mode in which the sheet is guided to the reverse path without using the third path, and FIG. 9B is a diagram illustrating the third path. It is a figure explaining the aspect to be used. It is a figure explaining the outline | summary of the structure in the image forming apparatus concerning a prior art.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified thru | or abbreviate | omitted suitably.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, a plotter, and a complex machine of these, for example, a liquid discharge recording type image forming apparatus using a recording head for discharging ink droplets is known. This liquid ejection recording type image forming apparatus ejects ink droplets from a recording head onto a conveyed paper to form an image, and the recording head moves in the main scanning direction to generate droplets. There are a serial type image forming apparatus that forms an image by discharging, and a line type image forming apparatus that uses a line type head that forms an image by discharging droplets without moving the recording head. Here, “paper” is not limited to paper, but includes OHP (overhead projector) paper (hereinafter referred to as OHP dedicated paper), which means that ink droplets, other liquids, and the like can adhere to it. Yes, it is also called a recording medium or recording medium, recording paper, recording paper, and the like. “Image formation” is used as a synonym for recording, printing, printing, printing, and the like.

  In the present application, the “image forming apparatus” of the liquid discharge method means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics and the like. In addition, “image formation” not only applies an image having a meaning such as a character or a figure to a medium, but also applies an image having no meaning such as a pattern to the medium. It also means to land on the medium. The “ink” is not limited to what is called ink, and is not particularly limited as long as it becomes a liquid when ejected. For example, a DNA sample, a resist, a pattern material, etc. Is also included. In addition, the “image” is not limited to a planar one, but includes an image given to a three-dimensionally formed image, and an image formed by three-dimensionally modeling a solid itself. In addition, the “image forming apparatus” is not limited to the liquid discharge type, but includes an apparatus that forms an image using an electrophotographic method.

[Example 1]:
The configuration of the image forming apparatus according to Example 1 is shown in FIG. In FIG. 1, an image forming apparatus 10 is disposed at a position facing a recording head unit 101 as an image forming unit that forms an image by ejecting liquid droplets onto a sheet 100 that is a recording medium. A conveying belt 112 that supports and conveys the sheet 100 to be printed, a sheet feeding cassette 103 that accommodates the sheet 100, and a sheet that is a member to be coated on the upstream side of the recording head unit 101 in the sheet conveying direction. 100 is provided with a treatment liquid coating apparatus 200 which is also a coating means for applying the treatment liquid 201 to 100.

  The recording head unit 101 includes a line-type liquid ejection head having a nozzle row in which a plurality of nozzles that eject droplets are arranged in a length corresponding to the paper width with the direction perpendicular to the paper surface of FIG. The recording heads 101y, 101m, 101c, and 101k are provided with ink droplets of respective colors of yellow (Y), magenta (M), cyan (C), and black (K). Note that the recording head can be mounted on the carriage as a serial type image forming apparatus. As with the recording head unit 101, the recording head unit 102 also includes recording heads 101y, 101m, 101c, and 101k, and a transport belt 112 that transports the paper 100 that is used for printing.

  The conveyor belt 112 is an endless belt, and is configured to circulate between the conveyor roller 121 and the tension roller 122. The paper 100 can be held on the transport belt 112 by, for example, a structure that performs electrostatic suction, suction by air suction, or other known transport means. Further, a conveying means using a roller pair can also be used.

  In addition to the recording head unit 101, another recording head 102 is provided above the recording head unit 101. Like the recording head unit 101, the recording head unit 101 includes a conveying belt 125, a conveying roller 123, a tension roller 124, and the like. Since the configuration is the same as that in the recording head unit 101, the description is omitted.

  The paper feeding unit 20 can be inserted and removed from the front side of the image forming apparatus main body 10 and in a direction perpendicular to the paper surface of FIG. 1, and includes a paper feeding cassette 103 that stacks and stores a large number of paper sheets 100, Are provided with a pickup roller 131 and a conveying roller pair 132 for separating and feeding out the paper 100 one by one.

  Further, a manual feed tray 105 that manually feeds paper that does not require application of the processing liquid 201 such as OHP dedicated paper, and a pickup roller 171 and a transport roller pair 172 for feeding the paper 100 one by one from the manual feed tray 105 are provided. I have.

  The processing liquid coating apparatus 200 includes a processing liquid container (not shown) in which a deformable PET (polyethylene terephthalate resin) film containing the processing liquid 201 is formed in a bag shape, and a processing liquid 201 supplied from the processing liquid container (not shown). A pump (not shown) for pumping and an application unit 210 for applying the processing liquid 201 to the paper 100 as a recording medium are provided. The processing liquid 201 in the processing liquid container (not shown) is sucked up by a pump (not shown) and supplied to the liquid chamber 202 in the coating unit 210 through a supply path (not shown) to prepare for coating.

  The processing liquid 201 supplied to the liquid chamber 202 is confirmed by a liquid level detection sensor (not shown) provided in the liquid chamber 202 to be within a predetermined level. The liquid level detection sensor uses, for example, an electrode pin method. Since the electrode pin method is a known technique, it will not be described in detail here, but the liquid level is detected by passing electricity through the electrode pins and conducting electricity between the electrode pins via the liquid. By this method, it is possible to prevent insufficient supply of the processing liquid 201 and supply of a predetermined amount or more to the liquid chamber 202.

  The application unit 210 includes a conveyance roller 234 that conveys the paper 100, an application roller 232 that applies the treatment liquid 201 to the paper 100 so as to face the conveyance roller 234, and supplies the treatment liquid 201 to the application roller 232 to form a liquid film. A squeeze roller 233 for reducing the thickness is provided.

  These rollers are arranged such that the application roller 232 is in contact with the conveying roller 234 and the squeeze roller 233 is in contact with the application roller 232. Then, a liquid film layer of the processing liquid 201 supplied by the squeeze roller 233 and the application roller 232 is formed, transferred to the transport roller 234 side by the rotation of the application roller 232, and applied to the paper 100 as a recording medium. The

  Here, the treatment liquid 201 is a modifying material that modifies the surface of the paper 100 by being applied to the surface of the paper 100. For example, the treatment liquid 201 is applied in advance to the paper 100 (not limited to paper as a material as described above) without unevenness, so that moisture of the ink can quickly permeate the paper 100 and increase the color component. Fixing agent (setting agent) that prevents bleeding (feathering, bleeding, etc.) and back-through by increasing viscosity and further drying, and increases productivity (number of images output per unit time). is there.

  In terms of composition, this treatment liquid 201 is, for example, cellulose that promotes moisture permeation with respect to a surfactant (any one of anionic, cationic, nonionic, or a mixture of two or more thereof). And the like (hydroxypropylcellulose and the like) and a base material such as talc fine powder. Further, fine particles can be contained.

(Conveyance path and process for image formation)
In this example, after the processing liquid 201 is applied to the first surface forming surface of the paper 100 sent out from the paper supply unit 20 by the processing liquid coating apparatus 200, the recording head units 101 and 102 are arranged in the vertical direction. First, the image on the first surface is formed by the recording head unit 101 arranged in the lower stage, and then the sheet is reversed, and then processed on the second surface forming surface of the paper 100 (the back surface of the first surface forming surface). After the treatment liquid 201 is applied by the liquid application device 200, an image on the second surface is formed by the recording head unit 102 arranged at the upper stage, and then sent to the paper discharge unit 30. The reason why the paper is reversed is that the processing liquid coating apparatus 200 that applies the processing liquid to only one side of the paper is shared by the processing liquid coating for image formation on the first and second sides. Further, this is because both the plurality of recording head units 101 and 102 form an image by ejecting ink from the same side with respect to the image forming surface of the paper.

  At the time of double-sided image formation, the paper 100 accommodated in the paper feed cassette 103 is separated and fed one by one by the pickup roller 131 and passes through the path indicated by the arrow 300 by the transport roller pair 132, and the registration rollers arranged in this path The pair is fed to the pair 133, and is sent from the registration roller pair 133 to the treatment liquid coating apparatus 200 by the transport roller pair 134 at a predetermined timing.

  The paper 100 on which the treatment liquid 201 is applied is switched by a swinging claw (solid line) 400 from a linear path extending on the extension of the arrow 300 to a path indicated by an arrow 301 branched to the left. The sheet 100 separated into the path indicated by the arrow 301 is sent by the transport roller pair 135, guided by a guide plate (not shown), sent onto the transport belt 112, and held on the transport belt 112. Then, it is transported along with the counter-clockwise circular movement of the transport belt 112, and droplets of each color are ejected from the recording heads 101y, 101m, 101c, 101k of the recording head unit 101 during this transport. An image of the first surface is formed on the surface to which the processing liquid 201 is applied when passing through.

  The paper 100 on which the image of the first surface is formed is sent out along the path indicated by the arrow 302 along with the circumferential movement of the transport belt 112 and is transported by the transport roller pair 136. The paper 100 being conveyed through the path indicated by the arrow 302 is guided to the switchback conveyance path 303 with its path regulated by a swinging claw (solid line) 401 and a swinging claw (solid line) 402.

  The switchback conveyance path 303 is provided with a reverse roller pair 137 that can be switched between forward and reverse, and constitutes a reversing means together with the switchback conveyance path 303, the reverse roller pair 137, the swinging claws 401, 402, and the like. The sheet 100 guided to the switchback conveyance path 303 advances to the left in the figure by the normal rotation of the reverse roller pair 137 until the rear end of the paper 100 passes through the swinging claw 401, and the rear end of the paper 100 passes through the swinging claw 401. Then, the reverse roller pair 137 rotates in the reverse direction and moves in the right direction in the figure to reverse the direction of travel, and the swinging claws 401 and 402 are switched to the positions indicated by broken lines, and the path is the refeed path indicated by the arrow 304. Are sequentially fed by the conveyance roller pairs 138, 139, and 140, merge into the conveyance path 300, and conveyed to the registration roller pair 133.

  The sheet 100 sent to the registration roller pair 133 is sent from the registration roller pair 133 to the processing liquid coating apparatus 200 along the conveyance path 300 by the conveyance roller pair 134 at a predetermined timing. In this state, the sheet 100 is conveyed through the switchback conveying path 303, so that the surface of the sheet is reversed compared to the case of conveying the first treatment liquid coating apparatus 200, and is opposite to the first surface. The second surface is directly opposed to the application roller 232. Therefore, the processing liquid 201 is applied to the second surface of the paper 100 by the application roller 232 while passing through the processing liquid coating apparatus 200.

  The paper 100 on which the processing liquid 201 is applied on the second surface proceeds upward in the vertical direction, which is an extension of the conveyance path 300, without being switched to the conveyance path 301 by the swinging claw (broken line) 400, and the conveyance path It is guided sideways by appropriate guiding means to the conveyance path indicated by arrow 305 that turns 301 outward. The sheet 100 separated into the conveyance path 305 is sent and held on the conveyance belt 125 via the conveyance path 305 by the conveyance roller pair 141. Then, while being conveyed along with the counter-clockwise circular movement of the conveying belt 125, droplets of each color are ejected from the recording heads 101y, 101m, 101c, and 101k of the recording head unit 102, and the processing liquid coating apparatus 200 is discharged. An image is formed on the second surface to which the processing liquid 201 is applied during passage.

  The sheet 100 on which images are formed on both sides is conveyed by the circular movement of the conveying belt 125 and is conveyed by the conveying roller 142 via the conveying path indicated by the arrow 306. The conveyance path 306 includes a pair of discharge rollers 143 that sends the paper 100 to the paper discharge unit 30, and the paper 100 is sent to the paper discharge unit 30 from the discharge roller 143.

  In the paper discharge unit 30, it is possible to select two types of whether the paper 100 is reversed and sent out to the paper discharge tray 104, or sent out to the paper discharge tray 104 without being reversed. When the paper is reversed and sent to the paper discharge tray 104, the paper 100 sent out from the discharge roller pair 143 is received and conveyed by the conveyance pair roller 144, and the swinging claw 403 (solid line) and the swinging claw 404 (solid line) are used. Then, the path is directed to the switchback conveyance path 307 and conveyed by the reverse roller pair 155. When the trailing end of the paper 100 passes through the swinging claw 403 and the swinging claw 404, the rotation direction of the reverse roller pair 155 is switched, and the swinging claw 403 and the swinging claw 404 are switched to positions indicated by broken lines, respectively. Thus, the paper 100 is reversed and sent to the paper discharge tray 104 through the discharge roller pair 156 of the paper discharge unit 30. In this case, the paper 100 is discharged onto the paper discharge tray 104 in a state where the paper 100 is reversed on the paper discharge tray 104 as compared with the state where the paper is fed from the discharge roller 143. In this example, the sheet is discharged with the first side facing up.

  On the other hand, when the paper is fed to the paper discharge tray 104 without being reversed, the swinging claw 403 is switched to the position of the broken line, and the paper 100 sent out from the discharge roller pair 143 is received by the transporting pair of rollers 144 and the swinging claw 403 (broken line) The paper 100 is not reversed by passing through the path indicated by the arrow 309 on the linear extension of the conveyance path 306 along the second line), and the second surface is placed on the discharge tray 104 via the discharge roller pair 156 of the discharge unit 30. And send it out. In this case, the sheet 100 is discharged to the discharge tray 104 without being reversed while being sent from the discharge roller 143. In this example, the sheet is discharged with the second side up.

  In this example, recording head units 101 and 102 are arranged in parallel in the vertical direction as a plurality of image forming means for forming an image by a recording head that discharges droplets toward the paper 100, and these recording head units 101, An image forming apparatus including a paper feeding unit 20 that feeds a paper 100 toward a paper 102 and a paper discharge unit 30 as a paper discharge unit that discharges the paper 100 after image formation. The path passes through the recording head unit 102 that is one of the recording head units 101 and 102 after exiting the paper feeding unit 20, and the first transport path leading to the paper discharge unit paper discharge unit 30. , On the downstream side of the processing liquid coating apparatus 200 disposed between the paper feeding unit 20 and the recording head unit 102 and upstream of the recording head unit 102. Branched from the branch position, passed through the recording head unit 101 which is the other one of the recording head units 101 and 102, and after being reversed, the first on the upstream side of the processing liquid coating apparatus 200 upstream of the branch position. It has a loop-shaped second conveyance path that merges with one conveyance path. In addition, while passing through the loop-shaped second transport path, the recording head unit 101 forms an image on the first surface and then reverses to join the first transport path. By forming an image on the second surface by 102, an image is formed on both surfaces to reach the paper discharge unit 30.

  In this configuration, the transport path 306 that prints on the second surface and travels toward the discharge portion does not overlap the re-transport path indicated by the arrow 304 toward the image formation on the second surface after printing on the first surface. In addition, there is no necessity for overlapping, and even when continuous image formation is performed, since the path has a degree of freedom in which the paths do not overlap with each other, printing of the first surface and the second surface is finished due to the configuration. No waiting state for printing can occur between the printed paper and the paper that has finished printing on the first side and is ready for image formation on the second side.

  Further, on the second conveyance path, the orientation of the sheet 100 by the switchback conveyance path 303, the reverse roller pair 137, the swinging claws 401, 402, and the like is arranged on the downstream side of the recording head unit 101 as another image forming unit. Since the reversing means for changing is provided, even if the processing liquid coating apparatus 200 is specified on one side facing the coating roller 232 as the processing liquid coating surface, only one of the processing liquid coating apparatuses 200 is installed. Before printing, paper can be fed with the processing liquid coating surface aligned, and the number of processing liquid coating apparatuses installed can be minimized.

  A supplementary description will be given of the switching of the route in the junction from the second conveyance path to the first conveyance path in FIG. FIG. 2 shows an enlarged view of the junction. A swinging claw 405 is disposed at the junction. When the sheet 100 is conveyed from the sheet feeding unit 20 to the treatment liquid coating apparatus 200, the swinging claw 405 is set up as shown in FIG. The conveyance path 300 is opened and the path of the sheet 100 fed by the conveyance roller pair 140 is blocked. When the paper 100 from the pair of transport rollers 140 is joined to the basic transport path, the paper 100 fed from the paper feeding unit 20 is transported by tilting the swinging claw 405 as shown in FIG. The path 300 is opened and the path of the paper 100 fed by the transport roller pair 140 is blocked.

  A supplementary description will be given of the switching of the route at the branching portion from the first conveyance path to the second conveyance path in FIG. FIG. 3 shows an enlarged branching portion. The swinging claw 400 is disposed at the branch portion. When the path of the paper 100 is not branched from the basic transport path, the swinging claw 400 is turned downward as shown in FIG. As a result, the paper 100 moves from the treatment liquid coating apparatus 200 to the recording head unit 102. When the path of the sheet 100 is branched from the basic transport path, the swinging claw 400 is tilted as shown in FIG. As a result, the paper 100 branches to the second transport path where the recording head unit 101 is located.

  A supplementary description will be given of the path switching at the junction of the path from the manual feed tray 105 in the first transport path in FIG. FIG. 4 shows an enlarged view of the junction. A swinging claw 406 is disposed at the junction. When priority is given to paper conveyance in the first conveyance path, the swinging claw 406 is tilted as shown in FIG. As a result, the sheet 100 from the treatment liquid coating apparatus 200 is directed to the conveyance roller pair 141. When giving priority to the OHP sheet or the like from the manual feed tray 105, the swinging claw 406 is turned sideways as shown in FIG. As a result, the OHP sheet or the like from the manual feed tray 105 is preferentially directed to the transport roller pair 141.

[Example 2]
In the image forming apparatus in Example 1 (FIGS. 1 to 4), only double-sided image formation is possible, the first side image is formed by the recording head unit 101, and the second side image is formed by the recording head unit 102. In other words, the relationship between the image forming surface and the image forming apparatus is fixed. Over time, there is a quantitative difference between the cumulative image forming amount of the first surface created by the recording head unit 101 and the cumulative image forming amount of the second surface created by the recording head unit 102. For this reason, in the long term, the degree of wear of the members is also biased according to the difference in the amount of image information processed between the recording head unit 101 and the recording head unit 102. May occur, resulting in a situation such as an increase in the frequency of machine downtime for maintenance.

  Therefore, in Example 2, while maintaining all the double-sided image forming functions in Example 1 as they are, in addition, it is possible to freely select either the recording head unit 101 or the recording head unit 102 so that the image can be formed. A third transport route is additionally set.

  A specific example is shown in FIG. In FIG. 5, the same conveyance path as the sheet conveyance path in FIG. 1 describing Example 1 is indicated by a thick arrow. In this example, in addition to that, as a member constituting the third conveyance path, the two conveyance roller pairs 136 and the conveyance rollers 143 are arranged so that the sheet that has come out from the conveyance roller pair 136 is guided to the conveyance roller pair 143. A pair of conveying rollers 150 is provided between them. In addition, a guide plate 600 is disposed immediately before the pair of conveyance rollers 143 so as to guide the sheet that has exited the conveyance roller pair 150 to the conveyance roller pair 150.

  By providing the conveyance roller pair 150 and the guide plate 600, and by switching both the swinging claw 401 and the swinging claw 402 to the positions indicated by the solid lines, the transport path on the downstream side of the recording head unit 101 is A third conveyance path connecting the conveyance roller pair 136 and the conveyance roller pair 143 is configured. This third transport path is on the first transport path by separating the path downstream from the transport roller pair 136 from the path to the reversing means mainly composed of the switchback transport path 303 and the reverse roller pair 137. The transport path joins the first transport path at a position immediately before the discharge roller pair 143 between the recording head unit 102 and the paper discharge unit 30. In the example of FIG. 6, a state in which the sheet 100 is positioned on the third transport path is illustrated.

  In this example, a third transport path is provided, and as shown in FIG. 6, the paths exiting the recording head units 101 and 102 are each configured to proceed to the paper discharge unit 30 without being refluxed. . Therefore, since there is a degree of freedom as to which of the recording head units 101 and 102 is used to form an image, when there is a bias in the cumulative image forming amount between the two recording head units, or when there is a possibility that it will occur. In the single-sided image forming mode, it is possible to select and form an image by selecting a recording head unit for each page so that the accumulated image forming amount is equalized.

  7A and 7B show the switching of the paper transport path. (A) The switchback path for the paper that has exited the transport roller pair 136 to the transport roller pair 138 through the reversing means mainly composed of the switchback transport path 303 and the reverse roller pair 137. And (b) a configuration comprising a guide plate and a swinging claw as means for switching between the third path through which the paper that has exited the conveyance roller pair 136 passes through the conveyance roller pair 150 and reaches the conveyance roller pair 143 is illustrated. FIG.

  As shown in FIG. 7, the conveyance path is formed between the opposing guide plates 601. A branch path that branches into a path that goes to the reverse roller pair 137 is provided at a position between the path connecting the transport roller pair 136 and the transport roller pair 150, and a swinging claw 407 is disposed at this branch portion. In addition, a branch path that branches to a path that goes to the transport roller pair 138 is provided at a position between the path connecting the swing claw 407 and the reverse roller pair 137, and the swing claw 408 is provided at the branch portion. These swinging claws 407 and 408 can swing with a base end portion indicated by a circle as a fulcrum.

  In the case (a), as shown in FIG. 7A, both the swinging claws 407 and 408 are placed at the positions indicated by solid lines, and the paper 100 from the transport roller pair 136 is rotated in the direction in which the paper 100 is pulled. It is guided to a reverse roller pair 137 during normal rotation. The reverse roller pair 137 is reversed when the trailing edge of the paper 100 passes through the swinging claw 408, and the paper 100 whose direction is reversed by switching the swinging claw 408 to the position indicated by the broken line is transferred to the transport roller pair 138. Can lead.

  In the case (b), as shown in FIG. 7B, the swinging claw 407 is placed at the position indicated by the solid line, and the paper 100 from the transport roller pair 136 is guided to the transport roller pair 150. Since the path to the swinging claw 408 is blocked by the swinging claw 407, it may be in the state of a solid line or a broken line.

  As for other means for switching the paper transport path, a swingable paper guide member is arranged at the branch point of the transport path, such as a rolling mill, and the swing shaft is used as a fulcrum or an eccentric cam is used. Then, the paper transport path can be switched by swinging the paper guide member.

[Example 3]
FIG. 8 shows an image forming apparatus. In this example, after the processing liquid 201 is applied to the first surface forming surface of the paper 100 delivered from the paper supply unit 20 by the processing liquid coating apparatus 200, the processing liquid 201 is disposed in the upper stage among the plurality of recording head units 101 and 102. An image on the first surface is formed first by the recording head unit 102, and then the sheet is reversed, and then processed by the processing liquid coating apparatus 200 on the second surface forming surface (the back surface of the first surface forming surface) of the paper 100. After applying the liquid 201, an image on the second surface is formed by the recording head unit 101 arranged at the lower stage, and then sent toward the paper discharge unit 30. The reason why the paper is reversed is that the processing liquid coating apparatus 200 that applies the processing liquid to only one side of the paper is shared by the processing liquid coating for image formation on the first and second sides. Further, this is because both the plurality of recording head units 101 and 102 form an image by ejecting ink from the same side with respect to the image forming surface of the paper.

  In FIG. 8, since the configurations of the paper feeding unit 20, the recording head units 101 and 102, the treatment liquid coating apparatus 200, and the paper discharge unit 30 have already been described, the same reference numerals are used and description thereof is omitted. Further, although the manual feed tray 105 described in Example 1 is not shown in FIG. 8, it can of course be configured similarly to FIG.

(Conveyance path and process for image formation)
The outline of this example is that a processing liquid 201 is applied to the first surface forming surface of the paper 100 sent out from the paper supply unit 20 by the processing liquid applying apparatus 200 and then arranged in the upper stage among the plurality of recording head units 101 and 102. The recording head unit 102 first forms an image on the first surface, and then reverses the paper, and then applies the treatment liquid coating device 200 on the second surface forming surface (the back surface of the first surface forming surface) of the paper 100. After applying the treatment liquid 201, an image on the second surface is formed by the recording head unit 101 arranged in the lower stage and then sent out toward the paper discharge unit 30. The reason why the paper is reversed is that the processing liquid coating apparatus 200 that applies the processing liquid to only one side of the paper is shared by the processing liquid coating for image formation on the first and second sides. Further, this is because both the plurality of recording head units 101 and 102 form an image by ejecting ink from the same side with respect to the image forming surface of the paper.

  Details will be described below. At the time of double-sided image formation, the paper 100 accommodated in the paper feed cassette 103 is separated and fed one by one by the pickup roller 131 and passes through the path indicated by the arrow 300 by the transport roller pair 132, and the registration rollers arranged in this path The pair is fed to the pair 133, and is sent from the registration roller pair 133 to the treatment liquid coating apparatus 200 by the transport roller pair 134 at a predetermined timing.

  The paper 100 coated with the treatment liquid 201 advances from the bottom to the top on the vertical path by extending the path indicated by the arrow 300 by the swinging claw (solid line) 400. In a state where the height of the recording head unit 102 arranged in the upper stage is reached, the path is bent in the horizontal direction and is sent by the conveying roller pair 141, followed by a leftward path indicated by an arrow 305, and sent onto the conveying belt 125. Held. Then, while being conveyed along with the counter-clockwise circular movement of the conveying belt 125, droplets of each color are ejected from the recording heads 102y, 102m, 102c, and 102k of the recording head unit 102. An image is formed on the first surface to which the processing liquid 201 is applied during passage.

  The sheet 100 on which the image is formed on the first surface is sent out from the recording head unit 102 and reaches the conveying pair roller 158, and a swinging claw (solid line) 412 and a guide plate 415 arranged in the vicinity of the downstream side of the conveying pair roller 158. Thus, the leading edge of the paper 100 is picked up and conveyed. In this way, the course can be changed in the diagonally upper right direction opposite to the previous direction, and the path is bent and curved, and further guided by a guide plate (not shown) and aligned in the lateral direction, and then the conveying pair rollers 160, 162, 163 Then, it is guided to the switchback conveyance path 312.

  The switchback conveyance path 312 is provided with a reverse roller pair 144 that can be switched between forward and reverse, and the switchback conveyance path 312, the reverse roller pair 144, and the swinging claw 413 constitute reversing means. The sheet 100 guided to the switchback conveyance path 312 by the swinging claw (dashed line) 413 advances to the right in the figure by the forward rotation of the reverse roller pair 144 until the rear end of the paper 100 passes through the swinging claw 413, and the rear end. When the part passes through the swinging claw (broken line) 413, the reverse roller pair 144 is reversely rotated to move to the left in the figure and the traveling direction is reversed, and the swinging claw 413 is switched to the position of the solid line. Are switched downward in the vertical direction, are sequentially sent by the conveying roller pairs 173 and 174, join the conveying path indicated by the arrow 300, and are conveyed to the registration roller pair 134.

  The sheet 100 sent to the registration roller pair 134 is sent from the registration roller pair 134 to the processing liquid coating apparatus 200 along the conveyance path 300 by the conveyance roller pair 134 at a predetermined timing. In this state, the sheet 100 is conveyed through the switchback conveying path 312, so that the surface of the sheet is reversed as compared with the case of the first treatment liquid coating apparatus 200 conveyance, and is opposite to the first surface. The second surface is directly opposed to the application roller 232. Therefore, the processing liquid 201 is applied to the second surface of the paper 100 by the application roller 232 while passing through the processing liquid coating apparatus 200.

  The paper 100 coated with the treatment liquid 201 on the second surface is switched to a path diagonally upward left by a swinging claw (broken line) 400 and is switched to a path indicated by an arrow 301 branched to the left. The sheet 100 separated into the path indicated by the arrow 301 is sent by the transport roller pair 135, guided by a guide plate (not shown), sent onto the transport belt 112, and held on the transport belt 112. Then, it is transported along with the counter-clockwise circular movement of the transport belt 112, and droplets of each color are ejected from the recording heads 101y, 101m, 101c, 101k of the recording head unit 101 during this transport. An image is formed on the second surface to which the processing liquid 201 is applied when passing through.

  The sheet 100 on which images are formed on both sides is conveyed by the circular movement of the conveying belt 112, conveyed by the conveying roller 175, and directed to the discharge roller pair 143 that feeds the sheet 100 to the sheet discharge unit 30. 143 is sent to the paper discharge unit 142. Since the transport mode of the paper 100 in the paper discharge unit 30 is the same as that described in Example 1, the same reference numerals are given in FIG. 8 and description thereof is omitted.

  In this example, recording head units 101 and 102 are arranged in parallel in the vertical direction as a plurality of image forming means for forming an image by a recording head that discharges droplets toward the paper 100, and these recording head units 101, An image forming apparatus including a paper feeding unit 20 that feeds a paper 100 toward a paper 102 and a paper discharge unit 30 as a paper discharge unit that discharges the paper 100 after image formation. The path passes through the recording head unit 101, which is one of the recording head units 101 and 102, after exiting the paper feeding unit 20, and the first transport path leading to the paper discharge unit paper discharge unit 30. , The downstream side of the processing liquid coating apparatus 200 disposed between the paper feeding unit 20 and the recording head unit 101 and the upstream side of the recording head unit 101. Branching from the branching position, passing through the recording head unit 102 which is another one of the recording head units 101 and 102, and after being reversed, the first side is upstream of the processing liquid coating apparatus 200 which is upstream of the branching position. It has a loop-shaped second conveyance path that merges with one conveyance path. In addition, while passing through the second transport path first, an image is formed on the first surface by the recording head unit 102 and then reversed and merged with the first transport path. By forming an image on two sides, an image is formed on both sides and reaches the paper discharge unit 30.

  In this configuration, a conveyance path including a conveyance roller pair 175 that prints on the second surface and travels toward the discharge portion, and a conveyance roller pair 160, 162, and 163 that completes printing on the first surface and proceeds to image formation on the second surface. In addition, there is no necessity of overlapping the conveyance paths, and even when continuous image formation is performed, there is a degree of freedom in a configuration in which the paths do not overlap each other as in this example. A print waiting state cannot occur between the paper on which the printing on the first side and the second side is finished and the paper on which the printing on the first side is finished and the image is formed on the second side.

  Further, on the second conveyance path, the reverse of changing the direction of the sheet 100 by the switchback conveyance path 312, the reverse roller pair 144, the swinging claw 4413, etc. on the downstream side of the recording head unit 102 as another image forming unit. Even if the treatment liquid application device 200 is specified on one side facing the application roller 232, only one of the treatment liquid application devices 200 is provided before printing by the recording head units 101 and 102. In addition, the sheet can be fed with the processing liquid coating surface aligned, and the number of processing liquid coating apparatuses installed can be minimized.

[Example 4]
In the image forming apparatus in Example 3 (FIG. 8), only double-sided image formation is possible, the first side image is formed by the recording head unit 102, and the second side image is formed by the recording head unit 101. In this way, the relationship between the image forming surface and the image forming apparatus is fixed. Over time, there is a quantitative difference between the cumulative image forming amount of the first surface created by the recording head unit 102 and the cumulative image forming amount of the second surface created by the recording head unit 101. For this reason, in the long term, the degree of wear of the members is also biased according to the difference in the amount of image information processed between the recording head unit 101 and the recording head unit 102. May occur, resulting in a situation such as an increase in the frequency of machine downtime for maintenance.

  Therefore, in Example 4, while maintaining all the double-sided image forming functions in Example 3 as they are, in addition, any of the recording head unit 101 and the recording head unit 102 can be selected freely so that the image can be formed. A third transport route is additionally set.

  A specific example is shown in FIG. In FIG. 9, among the paper transport paths in FIG. 8 describing Example 3, the transport paths used in this example are indicated by thick arrows. In this example, in addition to this, as a member constituting the third transport path, the swing claw 412 is switched to the horizontal broken line state so that the paper that has come out of the transport roller pair 158 is guided to the transport roller pair 143. A rotation driving means for the moving claw 412 is provided.

  A rotation driving means and a control means for determining the rotation position of the swinging claw 412 are provided. By switching the swinging claw 412 from the position indicated by the solid line to the position indicated by the broken line, the conveyance path on the downstream side of the recording head unit 102 is changed. It is possible to connect to the conveyance roller pair 143 after the conveyance roller pair 158. A path 500 indicated by a white arrow connected to the transport roller pair 143 after the transport roller pair 158 is referred to as a third transport path.

  The third transport path is a transport path that guides the paper 100 that has exited the recording head unit 102 to the discharge roller pair 143. As a result, each of the paths exiting the recording head units 101 and 102 is configured to proceed to the paper discharge unit 30 without being refluxed. There is a degree of freedom as to what to form. Therefore, if there is a bias in the accumulated image formation amount between the two recording head units, or if there is a possibility that it will occur, the single-sided image formation mode is set, and the recording for each page so that the accumulated image formation amount is equalized. An image can be formed by selecting the head unit.

  10 more specifically illustrates the path switching means using the swinging claw 412 and the guide plate 415 shown in FIG. 9 for switching the sheet transport path after the transport pair roller 158. In FIG. 10A, the paper 100 that has exited the transport roller pair 158 is guided toward the transport pair roller 160 using the feed of the paper 100 along a pair of opposed guide plates 650 a that are bent. Then, as an auxiliary means, a bending that is branched from the guide plate 650b toward the conveyance pair roller 160 in the guide plate 650b constituting the third conveyance path connecting the conveyance pair roller 158 and the conveyance pair roller 143. A swinging claw 414 is provided at the start position of the part. The swinging claw 414 scoops up the leading end portion of the paper 100 and guides it to the bent portion, and is held in a state of closing the conveyance path by the guide plate 650b. On the guide plate 650 b, on the downstream side of the swinging claw 414, a guide communicating with the guide plate 650 b on the downstream side of the swinging claw 414 so that the paper 100 that has exited the transporting pair roller 138 is smoothly sent to the transporting pair roller 143. The plate 650c is connected in such a manner that it is inclined toward the guide plate 650b as it goes downstream.

  In FIG. 10B, the swinging claw 414 is held in a state of being displaced so as to close the branch opening of the guide plate 650b. In this state, the paper 100 that has come out of the transport pair roller 160 can be guided to the transport pair roller 143, and the paper 100 that has come out of the transport pair roller 138 can also be guided to the transport pair roller 143. The conveyance control is performed with a time difference so that the sheets do not interfere with each other at the junction where the two conveyance paths merge.

DESCRIPTION OF SYMBOLS 1 Paper feed unit 2 Printing part unit 2a Variable paper guide 2c Recording head 2d Conveying roller 2e Variable paper guide 2f Opening 3b Variable paper guide 3c Conveying roller 3d Recording head 3f Conveying roller 3g Variable paper guide 10 Image forming apparatus 20 Section 30 Paper discharge unit 100, 100a, 100b, 100c, 100d Paper 101y, 101m, 101c, 101k Recording head 101, 102 Recording head unit 103 Paper feed cassette 104 Paper discharge tray 105 Manual feed tray 112, 125 Transport belt 121, 123 Transport Rollers 122 and 124 Tension rollers 131 and 171 Pickup rollers 132 Conveying roller pairs 133 Registration roller pairs 134, 135, 136, 138, 139, 140, 141, 142, 150, 158, 160, 162, 1 3, 172, 173, 174, 175 Conveying roller pair 137, 155, 144 Reverse roller pair 143, 156 Discharging roller pair 200 Processing liquid coating device 201 Processing liquid 203 Liquid chamber 210 Coating section 232 Coating roller 234 Conveying rollers M, N, O, P, Q, 300, 301, 302, 304, 305, 306, 309 Arrow 303, 312 Switchback transport path 307 Switchback transport path 600, 601, 415, 650a, 650b, 650c Guide plates 400, 401, 402 , 403, 404, 405, 406, 407, 408, 410, 412, 413, 414 Swing claw 500 path

JP 2003-305893 A

Claims (2)

A plurality of image forming units that form an image by a recording head that discharges droplets toward the recording medium are arranged in parallel in the vertical direction, and a paper feeding unit that sends out the recording medium toward the image forming unit; and the discharge portion of the recording medium after image formation is discharged from the exits the sheet feeding unit through one image forming means in said plurality of image forming means, first leading to the discharge unit a transport route, one other image in said first of said plurality of image forming means is branched from the branch portion provided between the said sheet feeder to said one image forming means of the conveying path Having a second transport path that passes through the forming means and joins at the merge section upstream of the branch section on the first transport path;
After the image is formed on the first surface of the recording medium by the other image forming unit, the image is formed on the second surface of the recording medium by the one image forming unit. in images forming device discharged to the sheet discharge unit to form images on both sides,
A treatment liquid applying device for applying a treatment liquid to one side of the recording medium on the first conveyance path and between the paper feeding unit and the one image forming unit; On the transport path, between the processing liquid coating apparatus and the one image forming means, and the merging section is on the first transport path, the paper feeding section and the processing liquid coating apparatus. An image forming apparatus comprising: a reversing unit that changes the direction of the recording medium on the second conveyance path on the downstream side of the other image forming unit on the second conveyance path. 2. The image forming apparatus according to claim 1, wherein a downstream transport path exiting the other image forming unit is branched from a path reaching the reversing unit, and is on the first transport path and the first transport path. An image forming apparatus comprising: a third transport path that joins between the two image forming units and the paper discharge unit.

Images