Treatment agent application device and image forming apparatus

Abstract

To provide a treatment agent liquid application device and an image forming apparatus capable of suppressing occurrence of banding application unevenness due to a treatment agent.SOLUTION: A treatment agent liquid application device mounted in an image forming apparatus includes an application roller that applies a treatment agent to a conveyed recording medium, a pressure roller that applies pressure to the application roller, a supply roller that supplies the treatment agent to the application roller, and a first control unit that rotates the application roller from when job information is acquired by the image forming apparatus until the recording medium reaches the application roller.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a treatment liquid application device and an image forming apparatus. [Background technology]

[0002] In image generating devices that print images on media using inkjet printing, a technique is known that aims to improve image quality by applying a treatment agent to the media during the image creation process.Typically, before the image creation process, the media is supported by an application roller containing the treatment agent and a transport roller on the opposite side across the media, and the application roller applies the treatment agent as the media passes by.

[0003] A pre-application liquid application device that applies a treatment agent to media using such an application roller has been disclosed that includes an application roller that applies treatment agent liquid to the media before image formation, a squeeze roller that presses against the application roller, a treatment agent liquid supply means that supplies treatment agent liquid to the nip between the application roller and the squeeze roller, and a squeeze pressure adjustment mechanism that adjusts the pressure of the squeeze roller against the application roller, and the pressure of the squeeze roller adjusted by the squeeze pressure adjustment mechanism so that it is approximately proportional to the media transport speed within the pre-application liquid application device (for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional technology, an application roller with an elastic layer on its outer periphery is sandwiched between a fixed roller and a pressure roller, and nips are formed with each of the two rollers.However, when the application roller is left in a non-rotating state, recesses are left on the application roller at two locations, one above the other, at a 180° pitch due to the nips.When media is inserted into the nip and the application roller rotates in accordance with the linear speed of the media, the amount of treatment agent applied to the recesses increases, resulting in the problem of banding-like uneven application at a pitch of half the circumference of the application roller.

[0005] The present invention has been made in view of the above, and has an object to provide a treatment agent liquid application device and an image forming apparatus that can suppress the occurrence of banding-like application unevenness due to the treatment agent. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the present invention provides a treatment agent liquid application device mounted on an image forming apparatus, characterized by comprising: an application roller that applies treatment agent to a recording medium being transported; a pressure roller that applies pressure to the application roller; a supply roller that supplies the treatment agent to the application roller; and a first control unit that rotates the application roller from the time job information is acquired by the image forming apparatus until the recording medium reaches the application roller. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the occurrence of banding-like coating unevenness caused by the treatment agent. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the overall configuration of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing another example of the overall configuration of the image forming apparatus according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of the configuration of the pre-coating unit of the image forming apparatus according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of the coating section of the pre-coating unit of the image forming apparatus according to the embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of a hardware configuration of the image forming apparatus according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating a control operation of the application roller of the application section of the pre-application unit of the image forming apparatus according to the embodiment. [Figure 7]FIG. 7 is a diagram illustrating an example of the configuration of functional blocks of the image forming apparatus according to the embodiment. [Figure 8] FIG. 8 is a diagram showing a preparation state before application of a treatment agent in an application section of a pre-application unit of a conventional image forming apparatus. [Figure 9] FIG. 9 is a diagram showing the state during application of a treatment agent in an application section of a pre-application unit of a conventional image forming apparatus. [Figure 10] FIG. 10 is a diagram showing a state in which banding-like coating unevenness occurs on a medium to which a treatment liquid has been applied by a pre-coating unit of a conventional image forming apparatus. [Figure 11] FIG. 11 is a diagram showing a state in which the coating section of the pre-coating unit of the image forming apparatus according to the embodiment is not in operation. [Figure 12] FIG. 12 is a diagram showing a preparation state before application of the treatment agent in the application section of the pre-application unit of the image forming apparatus according to the embodiment. [Figure 13] FIG. 13 is a diagram showing the state when the treatment agent is applied in the application section of the pre-application unit of the image forming apparatus according to the embodiment. [Figure 14] FIG. 14 is a diagram showing the state of the medium to which the treatment liquid has been applied by the pre-coating unit of the image forming apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, with reference to the drawings, embodiments of a treatment liquid application device and an image forming apparatus according to the present invention will be described in detail. Furthermore, the present invention is not limited to the following embodiments, and the components in the following embodiments include those that would be easily conceived by a person skilled in the art, those that are substantially the same, and those that are equivalent. Furthermore, various omissions, substitutions, modifications, and combinations of the components can be made without departing from the spirit of the following embodiments.

[0010] (Overall configuration of image forming apparatus) Fig. 1 is a diagram showing an example of the overall configuration of an image forming apparatus according to an embodiment. Fig. 2 is a diagram showing another example of the overall configuration of an image forming apparatus according to an embodiment. The overall configuration of an image forming apparatus 100 according to this embodiment will be described with reference to Figs. 1 and 2.

[0011] 1 is a commercial printing machine that forms images on media (recording media) such as paper using an inkjet method. The image forming apparatus 100 includes a paper feed unit 101, a pre-coating unit 108 (a treatment agent liquid application device), a resist unit 102, an imaging unit 103, a drying unit 104, a cooling unit 105, a reversing unit 106, and a paper discharge unit 107.

[0012] The paper feed unit 101 is a unit that separates and transports media one sheet at a time from the paper feed tray 120. The separated and transported media are fed to the pre-coating unit 108. The paper feed unit 101 can switch the transport path of the media depending on whether or not pre-coating of a treatment agent is performed in the pre-coating unit 108; when pre-coating is not performed, the paper feed unit 101 transports the media along path b shown in FIG. 1, and when pre-coating is performed, the paper feed unit 101 transports the media along path a. Note that in this embodiment, the paper feed unit 101 is based on the premise that pre-coating of the media is performed in the pre-coating unit 108, and therefore the paper feed unit 101 will be described as transporting the media along path a.

[0013] The pre-coating unit 108 is a unit (treatment agent liquid application device) for applying a pre-coating treatment agent to one or both sides of the medium that has been transported and fed along path a from the paper feed unit 101. The medium that has been pre-coated with the treatment agent by the pre-coating unit 108 is transported to the resist unit 102.

[0014] The registration unit 102 is a unit that properly corrects the orientation of the medium conveyed from the pre-coating unit 108. The medium whose orientation has been corrected by the registration unit 102 is conveyed to the imaging unit 103.

[0015] The imaging unit 103 is a unit that creates and prints an image by ejecting ink onto the medium transported from the registration unit 102. As shown in FIG. 1, the imaging unit 103 includes an image-creating transport drum 103a and an inkjet head 103b (ejection head).

[0016] The image creation transport drum 103a is a transport drum that rotates to transport the medium transported from the registration unit 102 toward the inkjet head 103b. The inkjet head 103b is an ejection head that ejects ink onto the medium transported by the image creation transport drum 103a to create and print an image.

[0017] The medium on which the image has been printed by the image forming unit 103 is transported to the drying unit 104 .

[0018] The drying unit 104 is a unit that dries the medium transported from the imaging unit 103. While the example of the image forming apparatus 100 shown in FIG. 1 is provided with one drying unit 104, this is not limiting and multiple units may be provided depending on the drying conditions. The medium dried by the drying unit 104 is transported to the cooling unit 105.

[0019] The cooling unit 105 is a unit that cools the dried media transported from the drying unit 104. The media cooled by the cooling unit 105 is transported to the reversing unit .

[0020] When double-sided printing is to be performed on the medium transported from the cooling unit 105, the reversing unit 106 is a unit that switches back the medium on path d as shown in Fig. 1, thereby reversing the medium, and transports it to the double-sided transport path 110. The medium transported to the double-sided transport path 110 is re-fed to the registration unit 102, where an image is printed on the second side, which is the reverse side of the first side on which an image has already been printed in the imaging unit 103. When single-sided printing is to be performed on the medium transported from the cooling unit 105, the reversing unit 106 transports the medium to the paper discharge unit 107 via path c as shown in Fig. 1.

[0021] The paper discharge unit 107 is a unit that discharges the media conveyed from the reversing unit 106 onto a paper discharge tray.

[0022] In the image forming apparatus 100 shown in FIG. 1, when the medium to be double-sided printed is inverted by the inversion unit 106, the medium is re-fed in the registration unit 102, i.e., downstream of the pre-coating unit 108. However, as in the image forming apparatus 100a shown in FIG. 2, the medium may be re-fed upstream of the pre-coating unit 108. The image forming apparatus 100a shown in FIG. 2 shows an example in which the medium is re-fed in the paper feed unit 101a upstream of the pre-coating unit 108. In FIG. 2, the configuration of the units downstream of the imaging unit 103 is the same as in FIG. 1, and therefore is not shown. The medium separated and transported from the paper feed tray 120 in the paper feed unit 101a is pre-coated with treatment agent in the pre-coating unit 108, has its orientation corrected in the registration unit 102a, and is transported to the imaging unit 103. In the case of a double-sided printing site, as in Figure 1, the media inverted by the inversion unit 106 passes through the double-sided transport path 110a, is re-fed by the paper feed unit 101a upstream of the pre-coating unit 108, and is transported again to the pre-coating unit 108, where a treatment agent is pre-coated on the second side, which is the back side of the first side that has already been pre-coated and image-printed, and the image-printing unit 103 then performs image-printing on the second side.

[0023] (Configuration of the first coating unit) Fig. 3 is a diagram showing an example of the configuration of a first coating unit of an image forming apparatus according to an embodiment. Fig. 4 is a diagram showing an example of the configuration of an application section of a first coating unit of an image forming apparatus according to an embodiment. The configuration of the first coating unit 108 of the image forming apparatus 100 according to this embodiment will be described with reference to Figs. 3 and 4.

[0024] As shown in FIG. 3, the pre-coating unit 108 has an application section 108a, entrance rollers 301 to 305, exit rollers 306 to 309, purge rollers 310 to 313, a re-entrance roller 314, and exit rollers 315 and 316.

[0025] Coating section 108a is a device that enters pre-coating unit 108 from direction H and coats the treatment agent onto the medium transported by inlet rollers 301 to 305. The configuration of coating section 108a will be described in detail later.

[0026] The entrance rollers 301 to 305 are transport rollers that transport the medium that has entered the pre-coating unit 108 from the direction H along the direction A to the coating section 108a.

[0027] Exit rollers 306-309 are rollers that transport media that have been coated with a treatment agent in coating unit 108a along directions B and C shown in Fig. 3. When coating both sides of a media with treatment agent, the media is coated on a first side in coating unit 108a, passes through exit rollers 306-309, and is then transported by purge roller 310 along direction D using a branching claw (not shown). On the other hand, when coating only one side of a media with treatment agent, the media is coated on a first side in coating unit 108a, passes through exit rollers 306-309, and is then transported by branching claws (not shown) along direction J using exit rollers 315 and 316 to registration unit 102.

[0028] Purge roller 310 is a transport roller for transporting the medium, the first surface of which has been coated with the treatment agent, to purge rollers 311 to 313 in order to switch back the medium.

[0029] Purge rollers 311-313 are transport rollers that transport the medium transported by purge roller 310 along directions E and G shown in Figure 3 and switch back. The medium switched back by purge rollers 311-313 is transported again by re-entry roller 314 along direction F to application unit 108a, where treatment agent is applied to the second surface. The paths in directions E and G taken by purge rollers 311-313 can also be used as purge paths.

[0030] The re-entrance roller 314 is a transport roller that transports the medium switched back by the purge rollers 311 to 313 along the direction F to the coating unit 108a.

[0031] Exit rollers 315 and 316 are transport rollers that transport the medium transported by exit rollers 307 to 309 in directions B and C to registration unit 102 in direction J.

[0032] 2, when the medium inverted by the reversing unit 106 is re-fed upstream of the first-coating unit 108, it is possible to apply a treatment agent to both sides of the medium in the first-coating unit 108 before the medium is transported to the registration unit 102a. Alternatively, the first-coating unit 108 may apply a treatment agent to only the first side, transport the medium to the registration unit 102a, have an image printed on the first side, and then the medium may pass through the double-sided transport path 110a and have a treatment agent applied to the second side in the first-coating unit 108. In this case, because there is no need to switch back the medium within the first-coating unit 108, the first-coating unit 108 may be configured not to include purge rollers 310-313 and re-entry roller 314.

[0033] Next, the specific configuration of the coating section 108a of the pre-coating unit 108 will be described with reference to FIG.

[0034] As shown in Fig. 4, the application unit 108a includes an application roller 201, a fixed roller 202, a squeeze roller 203, a pressure roller 204, a hold-down roller 205, a treatment liquid pan 211, an inlet sensor S1, and an outlet sensor S2. As shown in Fig. 4, the squeeze roller 203, the hold-down roller 202, the application roller 201, the pressure roller 204, and the hold-down roller 205 are arranged in this order from the bottom.

[0035] The application roller 201 is a roller that rotates to apply a liquid treatment agent supplied from the surface of the fixed roller 202 to the underside of the medium transported from the upstream transport path 212. The core of the application roller 201 is made of, for example, SUS303. As shown in FIG. 4, the application roller 201 is provided with an elastic layer 201a on its outer periphery. The elastic layer 201a is made of, for example, chloroprene rubber.

[0036] The fixed roller 202 is a supply roller that rotates to supply the treatment agent supplied from the squeeze roller 203 to the application roller 201. The fixed roller 202 is a metal roller made of, for example, SUS303.

[0037] The squeeze roller 203 is a roller that is impregnated with the processing agent filled in the processing agent liquid pan 211, and supplies the processing agent by rotating to the fixed roller 202. The squeeze roller 203 also has the function of stirring the processing agent filled in the processing agent liquid pan 211. The squeeze roller 203 has an elastic layer of chloroprene rubber or the like on its outer periphery, and a core made of, for example, SUS303.

[0038] The pressure roller 204 is a roller that applies pressure from above to the application roller 201. When a medium is transported from the upstream transport path 212 to the application roller 201, the pressure roller 204 presses the medium against the application roller 201. The pressure roller 204 is a metal roller made of, for example, SUS303.

[0039] The pressure roller 205 applies a downward load to the pressure roller 204 and the application roller 201, and rotates together with the rotation of the pressure roller 204. The pressure roller 205 has an elastic layer of chloroprene rubber or the like on its outer periphery, and its core is made of, for example, SUS303.

[0040] The medium transported from the upstream transport path 212 has treatment liquid applied to it by the application roller 201, and is then transported via the downstream transport path 213 to the exit roller 306 side shown in FIG. 3. The application roller 201, fixed roller 202, squeeze roller 203, and pressure roller 204 are rotated by a motor 206, which is the same drive source described below. Of these, the application roller 201 and squeeze roller 203 each rotate clockwise as viewed in FIG. 4, and the fixed roller 202 and pressure roller 204 each rotate counterclockwise as viewed in the same page.

[0041] The processing liquid pan 211 is a pan for storing liquid processing liquid.

[0042] The entrance sensor S1 is a sensor that detects the medium transported along the upstream transport path 212. The exit sensor S2 is a sensor that detects the medium that has been coated with the treatment agent by the application roller 201 and is being transported along the downstream transport path 213.

[0043] In the configuration of the application unit 108a as described above, as shown in Fig. 4, a nip portion 214 is formed between the application roller 201, which has an elastic layer 201a provided on its outer periphery, and the pressure roller 204, and a nip portion 215 is formed between the application roller 201 and the fixed roller 202. In the nip portion 214, the elastic layer 201a of the application roller 201 receives nip pressure from the pressure roller 204 and becomes concave. In the nip portion 215, the elastic layer 201a of the application roller 201 receives nip pressure from the fixed roller 202 and becomes concave. The treatment agent is applied to the medium transported from the upstream transport path 212 by passing through the nip portion 214.

[0044] (Hardware configuration of image forming device) 5 is a diagram showing an example of the hardware configuration of the image forming apparatus 100 according to the embodiment, and the hardware configuration of the image forming apparatus 100 according to the embodiment will be described with reference to FIG.

[0045] As shown in FIG. 5, the image forming apparatus 100 includes a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, an NVRAM (Non-Volatile Random Access Memory) 404, an external device connection I / F 408, a network I / F 409, an application section roller driver 411, a conveying roller driver 412, a sub-scanning driver 413, a sensor I / F 414, an inkjet head driver 420, an operation panel 430, and a separation drive circuit 440.

[0046] The CPU 401 is a computing device that controls the entire image forming apparatus 100. The ROM 402 is a non-volatile storage device that stores programs such as an IPL (Initial Program Loader). The RAM 403 is a volatile storage device that is used as a work area for the CPU 401.

[0047] The NVRAM 404 is a non-volatile storage device that stores various data such as programs and retains the various data even when the power to the image forming apparatus 100 is cut off.

[0048] The external device connection I / F 408 is an interface that is connected to an external device such as a PC (Personal Computer) via a USB (Universal Serial Bus) cable or the like, and communicates control signals, data to be printed, and the like with the external device.

[0049] The network I / F 409 is an interface conforming to TCP (Transmission Control Protocol) / IP (Internet Protocol) for data communication via the Internet or a LAN (Local Area Network), etc. The network I / F 409 may be a wired communication interface conforming to Ethernet (registered trademark), etc., or a wireless communication interface conforming to Wi-Fi (registered trademark), etc.

[0050] The coating section roller driver 411 is a drive circuit for driving the motor 206 that rotates the coating roller 201 , the fixed roller 202 , the squeeze roller 203 and the pressure roller 204 of the pre-coating unit 108 .

[0051] The transport roller driver 412 is a drive circuit for driving the entrance rollers 301 to 305, exit rollers 306 to 309, purge rollers 310 to 313, re-entrance roller 314, and exit rollers 315 and 316 of the pre-coating unit 108 to rotate independently.

[0052] The sub-scanning driver 413 is a drive circuit for driving the image forming transport drum 103a of the image forming unit 103 to rotate in order to transport the medium in the transport direction, that is, the sub-scanning direction.

[0053] The sensor I / F 414 is an interface for receiving signals detected by sensors such as the entrance sensor S1 and the exit sensor S2.

[0054] Inkjet head driver 420 is a drive circuit for controlling the ejection operation of inkjet head 103b.

[0055] The operation panel 430 is a device that displays setting information and various screens of the image forming apparatus 100, and includes a touch panel that accepts operation inputs from the user, an alarm lamp, and the like.

[0056] The separation drive circuit 440 is a drive circuit for moving the fixed roller 202 and the pressure roller 204 in a direction away from the application roller 201, or for moving them so as to contact the application roller 201 and form the nip portion 214 and the nip portion 215. The method of moving the fixed roller 202 and the pressure roller 204 by the separation drive circuit 440 can be, for example, a known method described in JP 2012-196955 A, etc., which uses a TR arm, a TR spring, and a TR cam.

[0057] The CPU 401, ROM 402, RAM 403, NVRAM 404, external device connection I / F 408, network I / F 409, application section roller driver 411, conveying roller driver 412, sub-scanning driver 413, sensor I / F 414, inkjet head driver 420, operation panel 430 and separation drive circuit 440 are capable of communicating data with each other via bus 410, which is an address bus and a data bus or the like.

[0058] Furthermore, the hardware configuration of image forming apparatus 100 shown in FIG. 5 is an example, and it is not necessary to include all of the components shown in FIG. 5, or other components may be included.

[0059] (Control operation of application roller) 6 is a diagram illustrating the control operation of the coating roller of the coating section of the pre-coating unit of the image forming apparatus according to the embodiment. The control operation of the coating section 108a of the pre-coating unit 108 of the image forming apparatus 100 according to the present embodiment will be described with reference to FIG.

[0060] The applicator 108a further includes a motor 206 and an encoder 207 shown in FIG.

[0061] The motor 206 is an electric motor for rotating the application roller 201 , the fixed roller 202 , the squeeze roller 203 and the pressure roller 204 .

[0062] The encoder 207 is a sensor that detects the number of rotations of the motor 206. The encoder 207 transmits the detected number of rotations of the motor 206 to an application unit roller driver 411, which will be described later.

[0063] As described above, the application unit roller driver 411 rotates the motor 206, which rotates the application roller 201, the fixed roller 202, the squeeze roller 203, and the pressure roller 204, by outputting a drive current to the motor 206. The encoder 207 detects the rotation speed of the motor 206 and feeds back the detected rotation speed to the application unit roller driver 411. That is, the application unit roller driver 411 performs feedback control by comparing the set rotation speed (target rotation speed) with the rotation speed fed back from the encoder 207, thereby rotating the motor 206 at the target rotation speed and rotating the application roller 201, the fixed roller 202, the squeeze roller 203, and the pressure roller 204 at the desired linear speed. Furthermore, the motor 206 is preferably an AC servo motor with high output and high responsiveness.

[0064] (Configuration and operation of functional blocks of image forming apparatus) 7 is a diagram showing an example of the functional block configuration of the image forming apparatus 100 according to the embodiment. The configuration and operation of the functional blocks of the image forming apparatus 100 according to the embodiment will be described with reference to FIG.

[0065] As shown in FIG. 7, the image forming apparatus 100 includes a job acquisition unit 500, a sensor detection unit 501, a roller control unit 502 (first control unit), a conveyance control unit 503, a memory unit 504, and a separation control unit 505 (second control unit).

[0066] The job acquisition unit 500 is a functional unit that acquires job information including print data to be printed from an external device or the like via the network I / F 409 or the like.

[0067] The sensor detection unit 501 is a functional unit that acquires, via the sensor I / F 414, a detection signal indicating that a medium has been detected by the entrance sensor S1 and the exit sensor S2.

[0068] The roller control unit 502 is a functional unit that controls the rotation of the application roller 201, the fixed roller 202, the squeeze roller 203, and the pressure roller 204 via the application unit roller driver 411. Specifically, the roller control unit 502 refers to a lookup table (described later) stored in the storage unit 504, and rotates the application roller 201 at an optimal linear speed corresponding to the preset type of media being transported within the image forming apparatus 100.

[0069] The transport control unit 503 is a functional unit that controls the rotation of the entrance rollers 301 to 305, exit rollers 306 to 309, purge rollers 310 to 313, re-entrance roller 314, and exit rollers 315 and 316 of the pre-coating unit 108 via the transport roller driver 412.

[0070] The storage unit 504 is a functional unit that stores a lookup table (an example of a table) that associates media types with optimal linear velocities of the application roller 201. The storage unit 504 is realized by the ROM 402 or the NVRAM 404 shown in FIG.

[0071] The separation control unit 505 is a functional unit that controls, via the separation drive circuit 440, the operation of moving the fixed roller 202 and the pressure roller 204 in a direction away from the application roller 201, or moving them to abut against the application roller 201 to form the nip portion 214 and the nip portion 215.

[0072] The above-described job acquisition unit 500, sensor detection unit 501, roller control unit 502, transport control unit 503, and separation control unit 505 are realized by executing a program by CPU 401 shown in Fig. 5. Note that at least some of the job acquisition unit 500, sensor detection unit 501, roller control unit 502, transport control unit 503, and separation control unit 505 may be realized by a hardware circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0073] Note that the functional units of image forming apparatus 100 shown in FIG. 7 are conceptually illustrated, and are not limited to such a configuration. That is, each functional unit of image forming apparatus 100 does not need to be configured as a clear software module as the block shown in FIG. 7, but rather the functions of each functional unit as a whole may be realized by executing a program in image forming apparatus 100. For example, multiple functional units illustrated as independent functional units in image forming apparatus 100 shown in FIG. 7 may be configured as a single functional unit. On the other hand, the function of one functional unit in image forming apparatus 100 shown in FIG. 7 may be divided into multiple units and configured as multiple functional units.

[0074] (Description of the operation of the pre-coating unit of a conventional image forming apparatus) Fig. 8 is a diagram showing the preparation state before application of treatment agent in the application section of a pre-coating unit of a conventional image forming apparatus. Fig. 9 is a diagram showing the state during application of treatment agent in the application section of a pre-coating unit of a conventional image forming apparatus. Fig. 10 is a diagram showing a state in which banding-like coating unevenness has occurred on media to which treatment agent has been applied in a pre-coating unit of a conventional image forming apparatus. The operation of the pre-coating unit of a conventional image forming apparatus will be described with reference to Figs. 8 to 10.

[0075] 8 shows the configuration of the application section of the pre-application unit of a conventional image forming apparatus, including the application roller 1201, fixed roller 1202, and pressure roller 1204. The application roller 1201 has an elastic layer 1201a formed on its outer periphery. In this configuration, a nip 1214 is formed between the application roller 1201, which has the elastic layer 1201a formed on its outer periphery, and the pressure roller 1204, and a nip 1215 is formed between the application roller 1201 and the fixed roller 1202. Before job information is acquired, similar to the image forming apparatus 100 according to the present embodiment described below, the application roller 1201 and the fixed roller 1202 are spaced apart, and the application roller 1201 and the pressure roller 1204 are also spaced apart, and the application roller 1201, the fixed roller 1202, and the pressure roller 1204 are all in a non-rotating state.

[0076] When the image forming apparatus acquires job information, media is fed from the paper feed unit, and therefore preparation for the coating operation by the coating roller 1201 must be completed by the time the media reaches the coating section of the pre-coating unit. For this reason, conventionally, as shown in Figure 8, when the image forming apparatus acquires job information, the application roller 1201, fixed roller 1202, and pressure roller 1204 remain non-rotating, and the fixed roller 1202 and pressure roller 1204 each abut against the application roller 1201, forming a nip portion 1214 between the application roller 1201 and the pressure roller 1204, and a nip portion 1215 between the application roller 1201 and the fixed roller 1202, and the apparatus waits.

[0077] As shown in FIG. 9 , when the medium P reaches the application section and the application roller 1201 begins application, the application roller 1201, the fixed roller 1202, and the pressure roller 1204 begin to rotate. However, because the application roller 1201 was in the standby state shown in FIG. 8 , two recesses 1214a and 1215a, spaced 180 degrees apart, are formed in the elastic layer 1201a of the application roller 1201, in the area receiving nip pressure from the fixed roller 1202 and the pressure roller 1204, as shown in FIG. 9 . As a result, when the medium P is inserted into the nip between the application roller 1201 and the pressure roller 1204, the amount of treatment agent increases in the recesses 1214a and 1215a, resulting in banding-like uneven application at a pitch corresponding to half the circumference of the application roller 1201, as shown in FIG. 10 . As described below, the image forming apparatus 100 according to this embodiment can suppress the occurrence of banding-like uneven application of the treatment agent.

[0078] (Details of operation of the coating section of the pre-coating unit of the image forming apparatus) FIG. 11 is a diagram showing a non-operating state of the coating section of the first coating unit of the image forming apparatus according to the embodiment. FIG. 12 is a diagram showing a preparation state before application of treatment agent in the coating section of the first coating unit of the image forming apparatus according to the embodiment. FIG. 13 is a diagram showing a state when treatment agent is applied in the coating section of the first coating unit of the image forming apparatus according to the embodiment. FIG. 14 is a diagram showing a state of media to which treatment agent has been applied by the first coating unit of the image forming apparatus according to the embodiment. Details of the operation of the coating section 108a of the first coating unit 108 of the image forming apparatus 100 according to the present embodiment will be described with reference to FIGS. 11 to 14.

[0079] In the application section 108a of the pre-application unit 108 according to this embodiment, before job information is acquired by the job acquisition section 500, the separation control section 505 separates the application roller 201 and the fixed roller 202 to release the nip pressure, and separates the application roller 201 and the pressure roller 204 to release the nip pressure, via the separation drive circuit 440, as shown in Fig. 11. In addition, in this state, the roller control section 502 keeps the application roller 201, the fixed roller 202, and the pressure roller 204 in a non-rotating state.

[0080] Next, when job information is acquired by the job acquisition unit 500, as in the conventional case described above, the media is fed from the paper feed unit 101. Therefore, preparation for the application operation by the application roller 201 must be completed by the time the media reaches the application unit 108a of the pre-application unit 108. However, when the application roller 201 is rotated, the treatment liquid supplied from the squeeze roller 203 and the fixed roller 202 comes into contact with air. This exposure causes the water in the treatment liquid to evaporate, increasing the viscosity of the treatment liquid and resulting in a decrease in quality. Furthermore, rotating the application roller 201 faster increases the frequency with which the treatment liquid comes into contact with air. Therefore, in this embodiment, when job information is acquired by the job acquisition unit 500, as shown in FIG. 12 , the separation control unit 505 first abuts the fixed roller 202 and the pressure roller 204 against the application roller 201, forming a nip 214 between the application roller 201 and the pressure roller 204, and a nip 215 between the application roller 201 and the fixed roller 202. 12 , from the time job information is acquired by the job acquisition unit 500 until the medium reaches the applying roller 201, the roller control unit 502 rotates the applying roller 201, the fixed roller 202, and the pressure roller 204 at a rotation speed that results in a linear speed that is lower than the linear speed corresponding to the medium. For example, it is desirable that the roller control unit 502 rotates the applying roller 201 at a rotation speed that results in a linear speed that is 1 / 10 or less of the linear speed corresponding to the medium, as specified in the lookup table stored in the storage unit 504. By rotating the applying roller 201, the fixed roller 202, and the pressure roller 204 slowly in this way, it is possible to suppress an increase in the viscosity of the treatment agent and to suppress the formation of depressions due to the nip pressure received from the fixed roller 202 and the pressure roller 204.

[0081] When medium P reaches applying roller 201 and applying operation is performed by applying roller 201, roller control unit 502 rotates applying roller 201, fixed roller 202, and pressure roller 204 at a rotation speed that corresponds to the linear velocity corresponding to medium P (linear velocity defined in the lookup table stored in storage unit 504), as shown in Fig. 13. Here, it is sufficient to determine that medium P has arrived at applying roller 201 when inlet sensor S1 detects medium P. As a result, the applying roller 201 applies the treatment agent to medium P with reduced formation of recesses, thereby suppressing the occurrence of banding-like uneven application of the treatment agent, as shown in Fig. 14.

[0082] As described above, in the pre-coating unit 108 of the image forming apparatus 100 according to this embodiment, the application roller 201 applies treatment agent to the transported medium, the pressure roller 204 applies pressure to the application roller 201, the fixed roller 202 supplies treatment agent to the application roller 201, and the roller control unit 502 rotates the application roller 201 from the time job information is acquired by the image forming apparatus 100 until the medium reaches the application roller 201. As a result, the application roller 201 applies treatment agent to the medium with reduced formation of recesses, thereby suppressing the occurrence of banding-like uneven application of the treatment agent.

[0083] Furthermore, in the pre-coating unit 108 of the image forming apparatus 100 according to this embodiment, the roller control unit 502 rotates the application roller 201 at a rotation speed that results in a linear speed that is lower than the linear speed corresponding to the media, from the time job information is acquired by the image forming apparatus 100 until the media reaches the application roller 201. This makes it possible to suppress an increase in the viscosity of the treatment agent, and also to suppress the formation of depressions due to the nip pressure received from the fixed roller 202 and the pressure roller 204.

[0084] In the above-described embodiments, when at least one of the functional units of image forming apparatus 100 is realized by executing a program, the program is provided by being pre-installed in a ROM or the like. In the above-described embodiments, the program executed by image forming apparatus 100 may be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (Compact Disk-Recordable), or a DVD (Digital Versatile Disc). In the above-described embodiments, the program executed by image forming apparatus 100 may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. In the above-described embodiments, the program executed by image forming apparatus 100 may be provided or distributed via a network such as the Internet. Furthermore, in the above-described embodiment, the program executed by the image forming apparatus 100 has a modular configuration including at least one of the above-described functional units, and in terms of actual hardware, the CPU 401 reads and executes the program from the above-described storage device (e.g., ROM 402, NVRAM 404, etc.), thereby loading and generating each of the above-described functional units onto the main storage device (RAM 403).

[0085] The aspects of the present invention are as follows. <1> A treatment liquid application device mounted on an image forming apparatus, an application roller that applies a treatment agent to the conveyed recording medium; a pressure roller that applies pressure to the application roller; a supply roller that supplies the treatment agent to the application roller; a first control unit that rotates the application roller from when job information is acquired by the image forming apparatus until the recording medium reaches the application roller; The treatment liquid application device is provided with: <2> the first control unit rotates the application roller at a rotation speed that is lower than a linear velocity corresponding to the recording medium from when job information is acquired by the image forming apparatus until the recording medium reaches the application roller; <1> 2. The treatment liquid application device according to claim 1. <3> the first control unit simultaneously rotates the application roller, the pressure roller, and the supply roller. <1> or <2> 2. The treatment liquid application device according to claim 1. <4> the first control unit rotates the application roller at a rotation speed that is equal to or less than 1 / 10 of a linear velocity corresponding to the recording medium from when job information is acquired by the image forming apparatus until the recording medium reaches the application roller; <2> 2. The treatment liquid application device according to claim 1. <5> the first control unit rotates the application roller at a rotation speed that corresponds to a linear velocity corresponding to the recording medium after the recording medium reaches the application roller. <1> ~ <4> 10. The treatment liquid application device according to claim 9, wherein the treatment liquid is a coating liquid. <6> the first control unit rotates the application roller, the pressure roller, and the supply roller simultaneously after the recording medium reaches the application roller. <5> 2. The treatment liquid application device according to claim 1. <7> a storage unit that stores a table in which the linear speed of the application roller is associated with each type of recording medium; the first control unit rotates the application roller at a rotation speed that is lower than the linear velocity corresponding to the recording medium defined in the table stored in the storage unit from when job information is acquired by the image forming apparatus until the recording medium reaches the application roller. <2> 2. The treatment liquid application device according to claim 1. <8> a second control unit that separates the pressure roller and the supply roller from the application roller before job information is acquired by the image forming apparatus; the first control unit controls the application roller, the pressure roller, and the supply roller to be non-rotating before the image forming apparatus acquires job information. <1> ~ <7> 10. The treatment liquid application device according to claim 9, wherein the treatment liquid is a coating liquid. <9> the second control unit causes the pressure roller and the supply roller to contact the application roller when job information is acquired by the image forming apparatus. <8> 2. The treatment liquid application device according to claim 1. <10> The aforementioned <1> ~ <9> a treatment liquid application device according to any one of the preceding claims; an ejection head that ejects ink onto the recording medium onto which the treatment agent has been applied by the treatment agent liquid application device to form an image; The image forming apparatus is provided with the above. [Explanation of symbols]

[0086] 100, 100a Image forming apparatus 101, 101a Paper feed unit 102, 102a resist unit 103 Imaging unit 103a Imaging transport drum 103b Inkjet head 104 Drying Unit 105 Cooling Unit 106 Reversing Unit 107 Paper output unit 108 First Coating Unit 108a Application part 110, 110a Double-sided transport path 120 Paper Tray 201 Application roller 201a Elastic layer 202 Fixed roller 203 Squeeze Roller 204 Pressure roller 205 pressure roller 206 Motor 207 Encoder 211 Processing liquid pan 212 Upstream transport route 213 Downstream transport route 214, 215 Nip section 301~305 Entrance roller 306~309 Exit roller 310~313 Purge roller 314 Re-entry roller 315, 316 Exit roller 401 CPU 402 ROM 403 RAM 404 NVRAM 408 External device connection I / F 409 Network I / F 410 Bus 411 Application unit roller driver 412 Conveyor roller driver 413 Sub-scan driver 414 Sensor I / F 420 Inkjet head driver 430 Operation Panel 440 Separation drive circuit 500 Job Acquisition Department 501 Sensor detection unit 502 Roller control section 503 Transport control unit 504 Storage section 505 Separation control section 1201 Application roller 1201a Elastic layer 1202 Fixed roller 1204 Pressure roller 1214 Nip section 1214a Recess 1215 Nip section 1215a Recess P Media S1 Inlet sensor S2 Exit Sensor [Prior art documents] [Patent documents]

[0087] [Patent Document 1] Patent No. 5821487

Claims

1. A treatment liquid application device mounted on an image forming apparatus, an application roller that applies a treatment agent to the conveyed recording medium; a pressure roller that applies pressure to the application roller; a supply roller that supplies the treatment agent to the application roller; a first control unit that rotates the application roller from when job information is acquired by the image forming apparatus until the recording medium reaches the application roller; A treatment liquid application device comprising:

2. 2. The treatment agent liquid application device according to claim 1, wherein the first control unit rotates the application roller at a rotation speed that results in a linear velocity that is lower than the linear velocity corresponding to the recording medium from the time job information is acquired by the image forming device until the recording medium reaches the application roller.

3. The treatment liquid application device according to claim 1 , wherein the first control unit rotates the application roller, the pressure roller, and the supply roller simultaneously.

4. 3. The treatment agent liquid application device according to claim 2, wherein the first control unit rotates the application roller at a rotation speed that results in a linear speed that is 1 / 10 or less of the linear speed corresponding to the recording medium from the time job information is acquired by the image forming device until the recording medium reaches the application roller.

5. The treatment liquid application device according to claim 2 , wherein the first control unit rotates the application roller at a rotation speed that corresponds to a linear velocity corresponding to the recording medium after the recording medium reaches the application roller.

6. The treatment liquid application device according to claim 5 , wherein the first control unit simultaneously rotates the application roller, the pressure roller, and the supply roller after the recording medium reaches the application roller.

7. a storage unit that stores a table in which the linear speed of the application roller is associated with each type of recording medium; 3. The treatment agent liquid application device according to claim 2, wherein the first control unit rotates the application roller at a rotation speed that results in a linear velocity that is lower than the linear velocity corresponding to the recording medium specified in the table stored in the memory unit, from the time job information is acquired by the image forming device until the recording medium reaches the application roller.

8. a second control unit that separates the pressure roller and the supply roller from the application roller before job information is acquired by the image forming apparatus; The treatment liquid application device according to claim 1 , wherein the first control unit stops the application roller, the pressure roller, and the supply roller from rotating before job information is acquired by the image forming device.

9. The treatment liquid application device according to claim 8 , wherein the second control unit brings the pressure roller and the supply roller into contact with the application roller when job information is acquired by the image forming device.

10. The treatment liquid application device according to claim 1 or 2; an ejection head that ejects ink onto the recording medium onto which the treatment agent has been applied by the treatment agent liquid application device to form an image; An image forming apparatus comprising:

Images