JP7200579B2 - Image forming apparatus and image forming system - Google Patents

Description

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

In an image forming apparatus that forms an image by ejecting droplets onto a recording medium, a treatment liquid that has the effect of making the state of the droplets adhered to the recording medium favorable for image formation is applied to the recording medium before image formation. There is known a device having a processing liquid application function. Also known is an image forming system configured by combining a treatment liquid coating device specialized for the function of applying a treatment liquid and an image forming apparatus having an image forming function.

The optimum amount of the treatment liquid to be applied in the image forming apparatus and image forming system differs depending on the type of recording medium. Therefore, in order to improve the quality of image formation, it is desirable to adjust the amount of processing liquid based on the recording medium. The treatment liquid is applied to the recording medium via the application roller. Therefore, the application amount of the treatment liquid correlates with the rotation speed of the application roller with respect to the recording medium.

In order to vary the amount of treatment liquid applied by the application roller, we developed a technology that changes the pressure of the roller that presses the recording medium against the application roller, and multiple application devices that are arranged in series to apply the treatment liquid in multiple layers. A technique for doing this has been disclosed (see, for example, Patent Literature 1).

In addition, since the application roller also serves to convey the treatment liquid while applying it, the amount of treatment liquid applied to the recording medium is also related to the conveyance speed of the application roller. As a technique for adjusting the application amount of the treatment liquid by adjusting the conveying speed of the application roller, a technique for controlling the application speed in order to vary the application amount of the treatment liquid has also been disclosed (for example, see Patent Document 2). reference).

There is also disclosed a technique for varying the application amount of the treatment liquid by changing the rotation speed of the application roller (see, for example, Japanese Patent Application Laid-Open No. 2002-200032).

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of varying application of a treatment liquid without lowering productivity in image forming processing.

To achieve the above object, the present invention relates to an image forming apparatus, which includes an image forming unit that forms an image by ejecting liquid droplets while conveying a recording medium, and an image forming unit that forms an image, and a treatment liquid applying section that applies a treatment liquid to the recording medium while conveying the recording medium; an image forming conveying speed that is a speed at which the recording medium is conveyed in the image forming section; and a control unit for controlling a liquid application transport speed, which is the speed at which the recording medium is transported, and the treatment liquid application unit rotates while being immersed in the treatment liquid stored in the liquid supply pan. A nip is formed between a drawing-up roller for drawing up the processing liquid and the drawing-up roller, and a nip is formed between the coating roller for receiving the processing liquid from the drawing-up roller and the coating roller with the recording medium interposed therebetween. a transfer roller for transferring the treatment liquid from the coating roller to the recording medium; and a first driving section for rotating the coating roller, wherein the control section controls the image forming and conveying speed to be constant. and controlling the first drive unit to rotate the coating roller based on the driving force from the first drive unit, thereby coating the recording medium with the treatment liquid while coating the recording medium with the image. It is characterized by conveying at the liquid coating conveying speed higher than the forming conveying speed .

According to the present invention, the application of the treatment liquid can be changed according to the recording medium without lowering the productivity in the image forming process.

1 is a system configuration diagram of a printing system that is an embodiment of an image forming system according to the present invention; FIG. 1 is a configuration diagram showing an embodiment of an internal configuration of a treatment liquid coating device that configures an image forming system according to the present invention; FIG. FIG. 4 is a diagram showing a conveying path of a recording medium in the treatment liquid coating apparatus according to the embodiment; 1 is a structural diagram showing an embodiment of an internal structure of an image forming apparatus that constitutes an image forming system according to the present invention; FIG. FIG. 2 is a diagram showing an example of the structure of a treatment liquid coating section provided in the treatment liquid coating apparatus according to the embodiment; 5 is a graph showing the relationship between the operation of the treatment liquid applying section and the amount of treatment liquid applied according to the present embodiment; FIG. 5 is a diagram showing an example of a data table that defines the operation of the treatment liquid applying section according to the embodiment; FIG. 5 is a diagram showing an example of a data table for correcting the operation of the treatment liquid applying section according to the embodiment;

[Summary of the present invention]
The present invention comprises: a treatment liquid applying section that applies a treatment liquid that acts on an image forming material (ink) to an image forming surface of a recording medium; an image forming section that forms an image on the image forming surface to which the treatment liquid is applied; The present invention relates to an image forming apparatus having The present invention also relates to an image forming system configured by linking an image forming apparatus for forming an image on an image forming surface and a treatment liquid applying apparatus for applying a treatment liquid to the image forming surface.

The treatment liquid used in the image forming apparatus and image forming system according to the present invention makes the state of the image forming surface of the recording medium on which the image is formed by the image forming material (liquid ink, etc.) suitable for image formation. It is a liquid that has the effect of Here, the "suitable state" is, for example, a state in which the image forming material (ink droplets) adhering to the image forming surface is aggregated to prevent bleeding of the ink, or a state in which show-through is prevented.

Therefore, the coating amount of the processing liquid has an important influence on the image quality. Therefore, it is desirable that the amount of the treatment liquid applied to the recording medium is optimal. Since the optimum coating amount differs depending on the type of recording medium (including type and brand; the same shall apply hereinafter), the coating amount can be changed according to the type of recording medium, and the image forming speed is not affected. is desirable.

In this respect, as in the technique disclosed in the above-mentioned Patent Document 1, in order to change the coating amount by changing the pressure contact load, the variable range becomes narrow and only fine adjustment is possible. I had a problem. When a plurality of coating apparatuses are arranged in series to perform multiple coating in order to widen the variable range of the coating amount, there is a problem that the coating apparatus becomes large and the cost of the apparatus becomes high.

Further, according to the technique disclosed in Japanese Patent Application Laid-Open No. 2002-200000, the application roller used for applying the treatment liquid to the recording medium and the transport roller used for transporting the recording medium are interlocked. Therefore, if the rotation speed of the application roller is lowered to lower the transfer speed of the application roller in order to increase the amount of treatment liquid applied, the rotation speed of the transfer roller also decreases, thereby lowering the transfer speed. When the conveying speed of the conveying rollers decreases, the image forming speed also decreases. That is, there is a problem that the image forming speed (printing speed) is sacrificed when the application amount of the treatment liquid is adjusted using the technique of Patent Document 1, and the productivity in the image forming process is lowered.

Further, as in the technique disclosed in Japanese Patent Application Laid-Open No. 2002-200001, when the application roller is provided with an adhesion amount regulating member and the application amount is changed according to the pressure contact state of the regulating member, the contact between the regulating member and the application roller high-precision parts are required to equalize the Moreover, there is also a problem that the range in which the coating amount can be varied is narrow and only fine adjustment is possible.

Furthermore, the technique disclosed in Patent Document 3 relates to coating on a roll-shaped medium (recording medium) that is connected from paper feeding to paper ejection. The speed becomes the same speed. In this configuration, changing the rotation speed changes the rotation speed of the application roller. Therefore, the technique disclosed in Japanese Patent Application Laid-Open No. 2002-200000 is a technique of varying the coating amount by slipping between the coating roller and the paper. According to this technique, the recording medium and the application roller are positively slipped. Therefore, there is a problem that contact between the edge of the recording medium and the coating roller accelerates the wear of the coating roller, shortening the life of the coating roller.

Note that the technology disclosed in Patent Document 3 can use a roll-shaped medium to which tension is continuously applied from paper feeding to paper ejection as a recording medium. Since it is not possible to continue to apply tension by transferring the paper between the rollers, there is also the problem that when the tension is released, the application rollers of different speeds come into contact with the recording medium, causing jams, which can cause transport failures. there were.

An image forming apparatus and an image forming system according to the present invention can solve the above-described problems associated with the prior art. controlling the conveying speed of the storage medium by the coating roller that applies the treatment liquid to the recording medium so as to maintain a constant relationship with the conveying speed of the conveying roller that conveys the recording medium during the image forming process; Let that be one of the main points. Here, "the conveying speed of the coating roller is kept in a constant relationship with the conveying speed of the conveying roller" means "controlling the conveying speed of the coating roller to be equal to or higher than the conveying speed of the conveying roller." It means that

Therefore, the image forming apparatus and the image forming system according to the present invention can set a wide adjustment range for the amount of treatment liquid to be applied, and finely adjust the adjustment range. To suppress an increase in size. Further, in the image forming apparatus and image forming system according to the present invention, even if the conveying speed (printing speed) in the image forming process is constant regardless of the type of the recording medium, an optimum amount according to the type of the recording medium is used. It is possible to apply the processing liquid without affecting the printing speed. Therefore, "cut paper" cut into a predetermined size can be used as the recording medium, and the variable range of the coating amount of the treatment liquid can be expanded, so that it can be used for a wide variety of recording media (media). It is possible to apply an optimum amount of the processing liquid and maintain the productivity of image formation.

Further, according to the image forming apparatus and the image forming system of the present invention, it is possible to prevent wasteful consumption of the processing liquid due to excessive coating amount. Also, it is possible to prevent "jam" caused by adhesion of the processing liquid to the conveying roller due to excessive application of the processing liquid. Furthermore, deterioration of image quality due to insufficient coating amount can be prevented. Furthermore, the image forming apparatus and image forming system according to the present invention can adopt a configuration that can be accommodated in a smaller space than the conventional technology, can reduce the manufacturing cost, and can prevent the quality deterioration of the coating roller due to wear. can also be prevented.

[Embodiment of Image Forming System]
First, an embodiment of an image forming system according to the present invention will be described. FIG. 1 is a schematic configuration diagram showing an outline of a printing system 1000 that is an embodiment of an image forming system. As shown in FIG. 1 , the printing system 1000 includes a feeding device 100 , a treatment liquid coating device 200 , a printer 300 as an image forming device, and a medium ejection device 400 . An image forming apparatus configured by combining the treatment liquid coating device 200 and the printer 300 is an embodiment of the image forming apparatus according to the present invention.

The feeding device 100 is a recording medium feeding device that feeds a sheet-like recording medium having an image forming surface on which an image is formed in an image forming process to the treatment liquid coating device 200 provided downstream of the sheet conveying path. be. The recording medium supplied from the feeding device 100 is, for example, "cut paper" cut into a predetermined size. In the following description of the present embodiment, it is assumed that the recording medium is cut paper, and will be referred to as "sheet 8".

The treatment liquid applying device 200 includes a treatment liquid applying section 210 that applies a treatment liquid that has an effect of aggregating ink and preventing show-through on the image forming surface of the sheet 8 .

The printer 300 includes an image forming unit 310 that ejects ink droplets onto the sheet 8 coated with the treatment liquid in the treatment liquid coating device 200 to form an image, and a drying unit that dries the treatment liquid and the ink droplets adhering to the sheet 8 . a portion 320; The printer 300 also includes a transport path for reversing and returning the sheet 8 from the drying section 320 to the image forming section 310 when printing on the front and back of the sheet 8 . In this way, ink droplets are ejected onto the back side of the image forming surface on which an image has been previously formed to form an image. It can be discharged to the discharge device 400 .

The medium ejection device 400 is a device that accommodates the sheets 8 on which image formation processing has been performed by the printer 300 .

[Structure of Treatment Liquid Coating Apparatus 200]
Next, the processing liquid coating device 200 according to this embodiment will be described with reference to the drawings. FIG. 2 is a configuration diagram showing the configuration of the treatment liquid coating device 200. As shown in FIG. As shown in FIG. 2 , the treatment liquid coating apparatus 200 has a treatment liquid application section 210 , a control section 220 , a treatment liquid supply section 230 , a carry-in section 240 and a carry-out section 250 .

The treatment liquid applying apparatus 200 also has a conveying path 260 including a plurality of conveying rollers and a plurality of paper guides. 251 and a second branch gate 252 are arranged.

The treatment liquid coating apparatus 200 also has a control section 220 that controls the overall operation. The control unit 220 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a rewritable non-volatile memory NVRAM ( Non-Volatie Random Access Memory), etc., and is an information processing unit that realizes processing functions by executing a computer program.

The control unit 220 controls the operation of the operating mechanism included in the treatment liquid coating apparatus 200 by causing the CPU to execute a control program recorded in the ROM. A RAM included in the control unit 220 is used as a work area when the control program is executed. In addition, the NVRAM of the controller 220 stores various data used in processing liquid application control processing, which will be described later. That is, in the control unit 220, the CPU reads out the control program stored in the ROM and develops it in the storage area of the RAM, and the CPU executes the control program while reading various data stored in the NVRAM. The NVRAM constitutes a storage unit for storing a coating amount data table and a coating amount correction data table, which will be described later.

The control unit 220 controls the conveying speed (liquid coating conveying speed) of the sheet 8 by the operation of the coating roller included in the treatment liquid applying unit 210 based on the conveying speed (image forming conveying speed) of the sheet 8 in the printer 300. do. In this case, the controller 220 controls the liquid application conveying speed to be faster than the image forming conveying speed. Specifically, the rotational speed of the drive source that rotates the application roller is controlled to be higher than the rotational speed of the drive source that defines the image forming transport speed, and the rotational speed of the application roller is changed by this control. to change the coating amount of the treatment liquid. Therefore, the control section 220 performs control so that the liquid application conveying speed can be arbitrarily changed while the image forming conveying speed is kept constant. That is, by using the image forming conveying speed as a reference and controlling the amount of change in the liquid applying conveying speed with respect to this reference, the liquid applying conveying speed can be arbitrarily changed to change the coating amount of the treatment liquid.

The control unit 220 also controls the conveying operation of the sheet 8 on the conveying path 260 and the switching operation between the first branch gate 251 and the second branch gate 252 .

The sheet 8, which is a single-fed medium discharged from the feeding device 100, is carried into the treatment liquid coating device 200 via the carry-in section 240, is conveyed by the conveyance path 260, reaches the treatment liquid coating section 210, and is coated with the treatment liquid. is applied. After that, it is conveyed to the unloading section 250 by the conveying path 260 and unloaded toward the printer 300 . 2 exemplifies the conveying direction of the sheet 8 on the conveying path 260. As shown in FIG.

[Mode of Conveyance in Treatment Liquid Coating Apparatus 200]
FIG. 3 is a diagram illustrating how the sheet 8 is conveyed when both sides of the sheet 8 are coated with the treatment liquid in the treatment liquid coating apparatus 200. As shown in FIG. When image formation processing is performed on both sides of the sheet 8 , that is, in the case of double-sided printing, it is necessary to apply the treatment liquid to both sides of the sheet 8 in the treatment liquid application device 200 . Therefore, the control unit 220 controls to convey the sheet 8 as shown in FIG. In FIG. 3, the conveying order of the sheets 8 is indicated by bold line arrows (A to J).

First, when the sheet 8 is conveyed from the feeding device 100 to the treatment liquid coating device 200 through the carry-in section 240, the sheet 8 is conveyed through the conveying paths A, B, and C in this order. As a result, the sheet 8 is conveyed to the treatment liquid application section 210 . In the treatment liquid application unit 210 , first, one side (surface) of the sheet 8 is applied with the treatment liquid. After that, the sheet 8 passes through the conveying path D to E. Here, the sheet 8 is conveyed to the conveying path F by switching the first branch gate 251 by the control unit 330 . Then, the sheet 8 reaches the conveying path G through the second branch gate 252 .

Here, the control unit 220 switches the second branch gate 252 to reverse the conveying direction of the sheet 8 . After that, the sheet 8 advances in the opposite direction as in the transport path H, passes through the switched second branch gate 252, and is again applied with the treatment liquid from the transport path I through the transport path C. It is transported to section 210 . At this time, the treatment liquid is applied to the rear surface of the sheet 8 . The sheet 8 coated with the treatment liquid on both sides passes from the transport path D to the transport path E thereafter. Then, the control section 220 switches the first branch gate 251 again, so that the sheet 8 passes through the conveying path J and is carried out from the carry-out section 250 . By the above operation, the sheet 8 coated with the treatment liquid on both sides is transferred to the printer 300 .

[Configuration of Printer 300]
Next, the printer 300 according to this embodiment will be described with reference to the drawings. FIG. 4 is a configuration diagram showing the configuration of the printer 300. As shown in FIG. As shown in FIG. 4, the printer 300 has an image forming section 310 and a drying section 320 . The printer 300 also has a conveying path 340 comprising a plurality of conveying rollers and a plurality of paper guides. 342 and .

The printer 300 also has a control section 330 that controls the overall operation. The control unit 330 has the same configuration as the control unit 220 already described, and includes a CPU, ROM, RAM, NVRAM and the like. The control unit 330 is an information processing unit that realizes a processing function for controlling the printer 300 by causing the CPU to execute a control program recorded in the ROM.

Control unit 330 controls the rotational speed of conveying roller 312 by controlling the rotational speed of conveying motor 313 included in image forming unit 310 . A conveying roller 312 and a conveying motor 313 are a conveying mechanism that conveys the sheet 8 to the image forming section 310 . Therefore, the control unit 330 controls the rotational speed of the conveying motor 313 to control the conveying speed of the sheet 8 with respect to the image forming unit 310 . The conveying speed of the sheet 8 in the image forming section 310 is referred to as "image forming conveying speed".

The control unit 330 also executes the operation of conveying the sheet 8 on the conveying path 340 and the operation of switching between the third branch gate 341 and the fourth branch gate 342 .

Note that the controller 330 operates in cooperation with the controller 220 of the treatment liquid coating apparatus 200 . In other words, the control unit 330 notifies the control unit 220 of data defining the image forming and conveying speed of the sheet 8 such as the rotation speed of the conveying roller 312 . The control unit 220 of the treatment liquid coating device 200 adjusts the rotation speed of the drive source for rotating the coating roller included in the treatment liquid coating unit 210 based on the image formation conveying speed notified from the control unit 330 as described above. Control. The conveying speed of the sheet 8 in the treatment liquid coating unit 210 controlled by the control unit 220 is referred to as "liquid coating conveying speed".

In the case of an image forming apparatus in which the treatment liquid coating device 200 and the printer 300 are integrated, the functions realized by the control section 220 and the control section 330 are combined to provide an integrated control section.

[Aspect of Conveyance in Printer 300]
The sheet 8, which is a single-fed medium discharged from the treatment liquid coating device 200, is conveyed by a conveying path 340 and reaches the image forming section 310, where ink liquid is discharged as droplets from a recording head 311, which is a liquid discharge head. An image is formed. After that, the sheet 8 passes through the drying section 320 by the conveying path 340, and passes through the drying section 320 while drying the image forming surface on which liquid droplets landed by the image forming process, processing liquid, and the like are adhered. 4 exemplifies the conveying direction of the sheet 8 on the conveying path 340. As shown in FIG.

When the sheet 8 discharged from the treatment liquid coating device 200 is to be subjected to image forming processing on only one side, the sheet 8 passes from the conveying route K to the conveying route L, and after the image forming processing, passes from the conveying route M to the third branch gate 341. It passes through and is ejected from the transport path O to the medium ejecting device 400 .

In the case where the sheet 8 having both sides coated with the treatment liquid is conveyed and image forming processing is performed on both sides, when the sheet 8 is carried in from the treatment liquid coating device 200, the conveyance paths K, L, and M are formed. After the sheet 8 is conveyed in the order of , the control unit 330 switches the third branch gate 341 . As a result, the sheet 8 is conveyed not to the conveying path 0 but to the conveying path P, and then passes through the fourth branch gate 342 to reach the conveying path Q. As shown in FIG.

Here, the controller 330 switches the fourth branch gate 342 to reverse the conveying direction of the sheet 8 . As a result, the sheet 8 advances in the opposite direction as in the transport path R, passes through the switched fourth branch gate 342, and is transported from the transport path S through the transport path T again. The sheet is conveyed to the image forming section 310 through paths K and L. In this manner, image forming processing is performed on the back surface of the sheet 8 .

Then, the sheet 8 on which images are formed on both sides is dried on the image forming surface while passing through the transport path M, and the control unit 330 switches the third branch gate 341 again, so that the transport path It passes through O and is discharged. By the operation described above, the sheet 8 on which a predetermined image is formed is discharged to the medium discharge device 400 .

[Configuration of Treatment Liquid Application Unit 210]
Next, the configuration of the treatment liquid applying unit 210 will be described. FIG. 5 is a diagram showing detailed configurations of the treatment liquid application unit 210 and the treatment liquid supply unit 230. As shown in FIG. As shown in FIG. 5, the treatment liquid applying section 210 includes a plurality of roller members. The treatment liquid application unit 210 includes a transfer roller 2201, an application roller 2204, and a drawing roller 2208 as a plurality of roller members.

The transfer roller 2201 is rotatably supported by one end of a TR arm 2202 whose intermediate position is supported by a swing fulcrum 2205 . One end and the other end of the TR arm 2202 swing vertically opposite to each other with the swing fulcrum 2205 as a boundary. A TR spring 2203 is connected to the other end of the TR arm 2202 . Therefore, the other end of the TR arm 2202 is pulled in the direction opposite to the direction of gravity, and as a result, the transfer roller 2201 is supported while being urged in the direction of gravity. As a result, the transfer roller 2201 is brought into elastic pressure contact with the application roller 2204 arranged on the gravity direction side.

When the sheet 8 passes through the nip formed between the transfer roller 2201 and the coating roller 2204 , the sheet 8 is coated with the processing liquid adhering to the outer peripheral surface of the coating roller 2204 .

In addition, a TR cam 2206 is arranged above the other end of the TR arm 2202 (the end to which the TR spring 2203 is connected), and the upper surface of the TR arm 2202 contacts the TR cam 2206. state. When the TR cam 2206 rotates, the position of the outer peripheral surface of the TR cam 2206 is displaced, and the contact surface of the TR cam 2206 is pushed down in the direction of gravity. Then, a pushing force in the direction of gravity is applied to the other end of the TR arm 2202 against the tensile force of the TR spring 2203 . A force applied to the other end of the TR arm 2202 by the rotation of the TR cam 2206 causes the transfer roller 2201 supported by one end of the TR arm 2202 to move in the direction opposite to the direction of gravity. This allows the transfer roller 2201 to move away from the application roller 2204 . A cam motor 2207 rotates the TR cam 2206 . That is, the nip between the transfer roller 2201 and the application roller 2204 is controlled based on the rotation of the cam motor 2207 .

The transfer roller 2201 rotates due to elastic pressure contact with the application roller 2204 . Note that the transfer roller 2201 and application roller 2204 can also be connected by a gear.

The coating roller 2204 is rotatably supported by the side plate of the housing of the treatment liquid coating section 210, and rotates using the driving force of the first motor 2225, which is the first driving section, as a driving source. In other words, the first motor 2225 rotates the application roller 2204 . That is, the rotational speed of the application roller 2204 is determined according to the rotational speed of the first motor 2225 . The supporting position of the application roller 2204 is movable in the vertical direction when the transfer roller 2201 side is the upper side and the drawing roller 2208 side is the lower side. The application roller 2204 is configured to be elastically pressed against the drawing roller 2208 by elastic pressure contact from the transfer roller 2201 .

The drawing-up roller 2208 is rotatably supported by the side plate of the supply liquid chamber 2209, and rotates using the driving force of the second motor 2226, which is the second driving section, as a driving source. In other words, the second motor 2226 rotates the pick-up roller 2208 . That is, the rotational speed of the drawing roller 2208 is determined according to the rotational speed of the second motor 2226 .

The supply liquid chamber 2209, which is a liquid supply pan, is swingably fixed to the housing of the processing liquid coating section 210 by a liquid chamber swing fulcrum 2213 provided on one surface of the outer surface. An arm 2210 is provided on the outer surface of the supply liquid chamber 2209 and on the surface opposite to the projection. The arm 2210 is urged upward (toward the transfer roller 2201 ) in the supply liquid chamber 2209 by a compression spring 2212 via a pin 2211 . Therefore, the supply liquid chamber 2209 is urged upward by the compression spring 2212 . Due to the urging of the compression spring 2212 , the drawing roller 2208 fixed to the supply liquid chamber 2209 can elastically press against the application roller 2204 .

A cam 2214 is in contact with the pin 2211 , and the rotation of the cam 2214 is configured to vary the pressing force of the compression spring 2212 . Therefore, the rotation of the cam 2214 can change the nip load between the application roller 2204 and the drawing roller 2208 . Further, the rotation of the cam 2214 changes the pressing force of the compression spring 2212 and changes the position of the supply liquid chamber 2209 . The rotary motion of the cam 2214 is driven by the third motor 2215 . Therefore, by controlling the drive of the third motor 2215 by the control unit 220 (see FIG. 2), contact and separation between the coating roller 2204 and the drawing roller 2208 can be controlled.

The supply liquid chamber 2209 stores a processing agent liquid 2216 as a processing liquid. The drawing-up roller 2208 is partially immersed in the treatment liquid 2216 . Since the drawing-up roller 2208 is in pressure contact with the application roller 2204 by elastic force, when the drawing-up roller 2208 rotates and adheres the processing agent liquid 2216 in the supply liquid chamber 2209 to the outer peripheral surface, the processing agent liquid 2216 is caused to adhere to the outer peripheral surface through the nip. The processing agent liquid 2216 is transferred from the drawing roller 2208 to the application roller 2204 . The coating roller 2204 moves the sheet 8 on the conveying path 260 while coating the processing agent liquid 2216 received from the drawing-up roller 2208 onto the sheet 8 at the nip with the transfer roller 2201 .

A liquid level sensor 2218 for detecting the liquid level of the processing agent liquid 2216 is provided in the supply liquid chamber 2209 . The liquid level sensor 2218 is attached at a position corresponding to the liquid level at which the processing agent liquid 2216 reaches an appropriate amount. By monitoring the output of this liquid level sensor 2218, it is configured to be able to monitor whether or not the processing agent liquid 2216 is in an appropriate amount. The appropriate amount of the processing agent liquid 2216 means a state in which the surface of the processing agent liquid 2216 is approximately at the rotation center of the drawing-up roller 2208 .

A temperature sensor 2227 for detecting the temperature of the processing agent liquid 2216 is installed inside the supply liquid chamber 2209 . The temperature sensor 2227 may be installed at a position immersed in the processing agent liquid 2216, or may be installed at a position where the temperature of the processing agent liquid 2216 can be calculated by measuring the environmental temperature of the supply liquid chamber 2209. . The temperature measured by the temperature sensor 2227 is notified to the controller 220 .

[Replenishing Operation of Processing Agent Solution 2216]
When the sheet 8 is coated with the processing agent liquid 2216, the processing agent liquid 2216 stored in the supply liquid chamber 2209 is consumed and the liquid level is lowered. The supply valve 2219 is opened to drive the supply pump 2220 when the liquid level sensor 2218 no longer detects the liquid level of the processing agent liquid 2216 . By driving the supply pump 2220 , the processing agent liquid 2216 held in the supply tank 2221 is sent into the supply liquid chamber 2209 .

When the liquid level reaches a predetermined level, the supply valve 2219 is closed and the supply pump 2220 is stopped. By the operation described above, the processing liquid applying section 210 is configured such that the liquid level of the processing agent liquid 2216 stored in the supply liquid chamber 2209 is kept constant.

Also, the properties of the processing agent liquid 2216 may change over time. For example, it must be considered that the processing agent liquid 2216 stored in the supply liquid chamber 2209 increases in viscosity after a certain amount of time has passed. Therefore, a drainage valve 2222, a drainage pump 2223, and a drainage tank 2224 are provided as a mechanism for discharging the processing agent liquid 2216 after a certain amount of time has passed. By opening the drain valve 2222 and driving the drain pump 2223 , the deteriorated processing agent liquid 2216 in the supply liquid chamber 2209 can be drained to the drain tank 2224 .

[Application process of treatment agent liquid 2216]
Next, the coating process according to this embodiment will be described. In the structure of the processing liquid applying unit 210 already described, when the second motor 2226 rotates the drawing roller 2208 , the processing liquid 2216 stored in the supply liquid chamber 2209 is drawn up by the drawing roller 2208 . This pumped processing agent liquid 2216 is carried to the contact position (nip) with the coating roller 2204 .

The processing agent liquid 2216 moves to the application roller 2204 in a predetermined amount by passing through the contact position between the drawing roller 2208 and the application roller 2204 . At this time, the moved processing agent liquid 2216 adheres to the outer peripheral surface of the application roller 2204 and becomes a thin film. As a result, the processing agent liquid 2216 reaches a predetermined amount. Therefore, at the nip between the drawing roller 2208 and the application roller 2204, the amount of the processing agent solution 2216 to be applied to the sheet 8 is measured.

The weighed processing agent liquid 2216 thinned into a thin film is conveyed to the contact position (nip) with the transfer roller 2201 by the rotation of the application roller 2204 . As the sheet 8 passes through the contact position between the coating roller 2204 and the transfer roller 2201 , the minute liquid layer on the surface of the coating roller 2204 is transferred to the sheet 8 . The application process is executed as described above, and the processing agent liquid 2216 stored in the supply liquid chamber 2209 is applied to the sheet 8 .

In the above configuration, the thickness of the liquid film (passing film thickness) of the processing agent liquid 2216 passing between the rollers that are in elastic pressure contact depends on the speed of each roller. Generally, the faster the pick-up roller 2208 rotates, the greater the amount of treatment fluid 2216 that is transferred to the application roller 2204 . That is, the thickness of the liquid film formed on the surface of the application roller 2204 is increased.

Therefore, when it is desired to increase the amount of the processing agent liquid 2216 to be applied to the sheet 8, the rotational speed of the pick-up roller 2208 driven by the second motor 2226 is increased to increase the amount of the processing agent liquid 2216 supplied to the application roller 2204. When the application roller 2204 applies the processing agent solution 2216 to the sheet 8, the rotational speed of the application roller 2204 may be reduced.

[Relationship Between Application Amount of Treatment Agent Liquid 2216 and Rotational Speed of Application Roller 2204]
Next, the relationship between the coating amount of the processing agent liquid 2216 on the sheet 8 and the rotational speed of the coating roller 2204 in the processing liquid coating section 210 according to this embodiment will be described using the graph of FIG. In the graph shown in FIG. 6, the vertical axis represents the amount of the processing agent solution 2216 applied to the sheet 8, and the horizontal axis represents the "rotation speed ratio (peripheral speed ratio)" of the coating roller 2204 and the drawing roller 2208. FIG.

Three graphs are drawn in FIG. Graph G1, graph G2, and graph G3 distinguish cases where the rotation speed of the drawing roller 2208 is constant and the rotation speed of the coating roller 2204 is different. Graph G1 represents the case where the rotation speed of application roller 2204 is “speed S1”. Graph G2 represents the case where the rotation speed of application roller 2204 is “speed S2”. Graph G3 represents the case where the rotation speed of application roller 2204 is “speed S3”.

Each speed has a relationship of "speed S1<speed S2<speed S3". It is assumed that the conveying speed of the conveying roller 312 and the conveying roller 2204 are the same when the rotational speed of the applying roller 2204 is the speed S1. That is, the graph of the speed S1 shows the relationship between the peripheral speed ratio and the coating amount when the liquid application conveying speed is the same as the image forming conveying speed.

When the rotation speed of the first motor 2225 is set to the speed S2, the rotation speed of the coating roller 2204 becomes faster than the rotation speed of the conveying roller 312 . That is, the graph of the speed S2 represents the relationship between the peripheral speed ratio and the coating amount when the liquid application conveying speed is faster than the image forming conveying speed.

When the rotation speed of the first motor 2225 is set to the speed S3, the rotation speed of the application roller 2204 becomes even faster than the rotation speed of the conveying roller 312 . That is, the graph of the speed S3 represents the relationship between the peripheral speed ratio and the coating amount when the liquid application conveying speed is higher than the image forming conveying speed.

As shown in the graph of FIG. 6, by varying the rotation speed of the application roller 2204 between speed S1 and speed S3, for example, when the peripheral speed ratio is "peripheral speed ratio: C", the processing agent liquid 2216 The coating amount can be varied between "Range A".

The controller 220 varies the rotational speed of the coating roller 2204 based on the rotational speed of the transport roller 312, and controls the rotational speed of the coating roller 2204 so that "image forming transport speed≦liquid coating transport speed." . Therefore, the control section 220 has a function of receiving notification of the rotation speed of the conveying motor 313 from the control section 330, and controls the rotation speed of the first motor 2225 in response to this notification. As a result, the conveying speed of the conveyed sheet 8 coated with the processing agent liquid 2216 by the applying roller 2204 is set to be equal to or higher than the conveying speed when the image forming process is performed, and the optimum amount of application to the sheet 8 is realized. The conveying speed of the sheet 8 coated with the processing agent liquid 2216 in the processing liquid coating section 210 decreases until it reaches the image forming section 310 . Therefore, the application amount of the processing agent liquid 2216 to the sheet 8 can be changed while the image forming processing speed (printing speed) remains constant. 8 can be applied with an appropriate amount of processing agent liquid 2216 .

In addition, in the processing liquid applying unit 210 according to the present embodiment, when the rotational speed of the applying roller 2204 is kept constant (when the liquid coating conveying speed is kept constant), by changing the circumferential speed ratio, the graph G1 , the coating amount of the processing agent liquid 2216 can be varied within the "range B".

Here, the position where the peripheral speed ratio is determined is between the application roller 2204 and the drawing roller 2208 . In other words, there is no contact with the edge of the sheet 8, which is the recording medium, and there is a difference in peripheral speed between the rollers on which the processing agent liquid 2216 exists. 2204 and the drawing-up roller 2208 are not affected by wear and the like, and high durability can be ensured.

Furthermore, according to the processing liquid coating unit 210 according to the present embodiment, by combining the coating speed and the circumferential speed ratio, the coating amount of the processing agent liquid 2216 can be reduced in the combined range of “range A” and “range B”. can be changed. While maintaining the productivity of the image forming process, it is possible to widen the range in which the coating amount of the processing agent liquid 2216 is changed. By expanding the variable range of the coating amount of the processing agent liquid 2216, it is possible to apply the processing agent liquid 2216 with the optimum coating amount for each of various recording media of various types. can be done.

[Example of coating amount data table]
The treatment liquid applying apparatus 200 according to the present embodiment is referred to when the control 220 controls the rotation speed of the application roller 2204 in order to apply the optimum treatment liquid 2216 according to the type of the sheet 8 that is the recording medium. The application amount data table to be used is stored in the storage unit of the control unit 220 .

FIG. 7 is a control table T1, which is an embodiment of a coating amount data table. The control table T1 has a structure in which the rotation speed and peripheral speed ratio of the first motor 2225 corresponding to the type of the seat 8 are linked. The data stored in the control table T1 is data for defining the liquid coating and conveying speed so that the coating amount of the processing agent liquid 2216 corresponding to the type of the sheet 8 is the optimum amount.

The treatment liquid applying apparatus 200 may be configured to include a sensor for detecting the type of the sheet 8 in the carry-in section 240, or receive an input such as the type of the sheet 8 via an operation panel provided in the treatment liquid applying apparatus 200 or the printer 300. may be configured.

When the control unit 220 executes the control program to apply the treatment liquid 2216 to the sheet 8, the control table T1 is read based on the type of the sheet 8 detected or the type of the sheet 8 input in advance. to select the rotational speed of the first motor 2225 and the peripheral speed ratio. For example, if the type of the sheet 8 is "P", the rotation speed of the first motor 2225 is "P1" and the peripheral speed ratio is "P2".

The control unit 220 also determines the rotation speed of the drawing roller 2208 (the rotation speed of the second motor 2226) based on the read P1 and P2.

The control unit 220 then controls the first motor 2225 to rotate at the rotational speed "P1" and the second motor 2226 to rotate at the rotational speed calculated from the peripheral speed ratio "P2". As a result, the processing agent liquid 2216 can be applied in an amount corresponding to the sheet 8 to be coated with the processing agent liquid 2216 .

Note that control data corresponding to the type of the sheet 8 that is not stored in advance in the control table T1 is arbitrarily input using the operation panel provided in the treatment liquid coating apparatus 200 or the operation panel provided in the printer 300, and sent to the control unit 220. It can also be stored.

Moreover, it is also possible to specify a coating amount that is not based on the type of the sheet 8 via the operation panel each time processing is performed. As a result, the amount of processing agent liquid 2216 to be applied can be reduced and the consumption amount of processing agent liquid 2216 can be suppressed without emphasizing the quality of the image forming process.

As described above, the treatment liquid coating apparatus 200 according to the present embodiment stores the basic setting of the coating amount for each type of the sheet 8 as the control table T1, and can arbitrarily set the coating amount via the operation panel. can also This makes it possible to change the appropriate coating amount of the processing agent liquid 2216 to correspond to a wide range of types of paper 9 .

As for the setting of the coating amount for each type of sheet 8, in the case of the sheet 8 having the property that the processing agent liquid 2216 easily permeates, for example, in the case of plain paper or recycled paper, graph G1 (see FIG. 6) is used. , the same speed as the image forming conveying speed. On the other hand, in the case of the sheet 8 having characteristics that the processing agent liquid 2216 is difficult to permeate, for example, in the case of gloss coated paper, cast coated paper, film, etc., the image is shown in graph G2 or graph G3 (see FIG. 6). The liquid application conveying speed should be higher than the forming conveying speed. This is because the penetrability of the processing agent liquid 2216 into the sheet 8 affects the amount of application, and the amount of application is greater for the types that are easier to permeate. Therefore, for sheets 8 of a type that requires a large amount of coating, variation in the amount of coating can be suppressed depending on the type of sheet 8 by suppressing the amount of coating by controlling the liquid coating and conveying speed.

[Example of coating amount correction data table]
As already described, the treatment liquid application unit 210 according to this embodiment includes the temperature sensor 2227 that measures the temperature of the treatment agent liquid 2216 in the supply liquid chamber 2209 . The optimum coating amount for the sheet 8 is affected not only by the type of the sheet 8 but also by the temperature of the processing agent liquid 2216 . This is because the viscosity of the treatment agent liquid 2216 changes depending on the temperature. The higher the temperature, the lower the viscosity of the processing agent liquid 2216, so the coating amount tends to decrease. Therefore, the temperature sensor 2227 appropriately measures the temperature of the processing agent liquid 2216, and based on the measurement result, the value read from the control table T1 is corrected.

The control unit 220 stores a coating amount correction data table for correcting control data for applying the optimum processing agent liquid 2216 according to the processing agent liquid 2216 in the storage unit. The coating amount correction data table illustrated here stores correction coefficients as a temperature correction table.

FIG. 8 is an example of a correction table T2, which is an embodiment of the temperature correction table. The correction table T2 has a structure in which a coefficient for correcting the rotation speed of the first motor 2225 and a coefficient for correcting the circumferential speed ratio are linked with respect to the temperature range of the processing agent liquid 2216 .

The control unit 220 detects the type of the sheet 8 by a sensor provided in the carry-in unit 240, or receives an input such as the type of the sheet 8 via an operation panel provided in the treatment liquid coating device 200 or the printer 300. Identify the control values in table T1. Then, based on the temperature of the processing agent liquid 2216 measured by the temperature sensor 2227, the correction table T2 is referenced to specify the correction coefficient.

For example, when the type of the seat 8 is “P” and the measured temperature is “12° C.”, the value obtained by multiplying the rotation speed “P1” of the first motor 2225 by the coefficient “X1” is 2225 rotation speed. Also, the rotation speed of the second motor 2226 is controlled based on the value obtained by multiplying the peripheral speed ratio “P2” by the coefficient “Y1”. As a result, the higher the temperature of the processing agent liquid 2216, the faster the coating speed and the greater the peripheral speed ratio.

Although the processing liquid applying unit 210 measures the temperature of the processing agent liquid 2216 in the liquid in the supply liquid chamber 2209, the same control can be executed by measuring the environmental temperature in the vicinity of the liquid. . This makes it possible to follow fluctuations in the optimum coating amount due to temperature changes in the treatment agent liquid 2216 .

According to the printing system 1000 including the treatment liquid applying device 200 and the printer 300 according to the present embodiment described above, it is possible to expand the range in which the application amount of the treatment agent liquid 2216 can be varied according to the status of the image forming process. . In addition, it is possible to accommodate various types of seats 8 in a small space at a low cost. Furthermore, by appropriately controlling the applied amount of the processing agent liquid 2216, it is possible to prevent wasteful consumption of liquid due to an excessive applied amount, and prevent jams due to excessive application.

According to the printing system 1000 including the treatment liquid coating device 200 and the printer 300 according to the present embodiment described above, it is possible to prevent deterioration in image quality due to insufficient application of the treatment liquid 2216 .

Although the invention made by the present inventor has been specifically described above based on the preferred embodiments, the present invention is not limited to those described in the above embodiments, and various modifications can be made without departing from the gist of the invention. It goes without saying that this is possible.

100 : Feeding device 200 : Treatment liquid application device 210 : Loading unit 220 : Treatment liquid application unit 230 : Treatment liquid supply unit 240 : Carrying out unit 250 : Conveyance path 300 : Printer 310 : Image forming unit 320 : Drying unit 400 : Medium Ejecting device 1000 : Printing system 2201 : Transfer roller treatment liquid application unit 2201 : Transfer roller 2202 : TR arm 2203 : TR spring 2204 : Application roller 2205 : Rocking fulcrum 2206 : TR cam 2207 : Cam motor 2208 : Drawing up roller 2209 : Supply liquid Chamber 2210 : Arm 2211 : Pin 2212 : Compression spring 2213 : Liquid chamber rocking fulcrum 2214 : Cam 2215 : Third motor 2216 : Treatment liquid 2217 : First measuring roller 2218 : Liquid level sensor 2225 : First motor 2226 : Second Two motors 2227: medium sensor 2228: second metering roller 2319: supply valve 2320: supply pump 2321: supply tank 2322: drainage pump 2323: drainage valve 2324: drainage tank

JP 2012-196955 A JP 2006-346924 A JP 2014-34167 A

Claims (7)

an image forming unit that forms an image by ejecting droplets while conveying a recording medium;
a treatment liquid application unit that applies a treatment liquid to the recording medium while conveying the recording medium before the image is formed;
a control unit that controls an image forming transport speed, which is the speed at which the recording medium is transported in the image forming unit, and a liquid coating transport speed, which is the speed at which the recording medium is transported in the treatment liquid coating unit; with
The treatment liquid application unit includes:
a pumping roller that rotates while being immersed in the processing liquid stored in the liquid supply pan and pumps up the processing liquid;
a coating roller that receives the processing liquid from the drawing roller at a nip formed between the drawing roller;
a transfer roller that forms a nip with the application roller via the recording medium and transfers the treatment liquid from the application roller to the recording medium;
and a first drive unit that rotates the application roller,
The control unit controls the image forming and conveying speed to be constant, controls the first driving unit, and rotates the application roller based on the driving force from the first driving unit, thereby rotating the recording medium. conveying the recording medium at the liquid coating conveying speed equal to or higher than the image forming conveying speed while applying the treatment liquid to the
An image forming apparatus characterized by: comprising a second drive unit for rotationally driving the drawing-up roller,
2. The image forming apparatus according to claim 1 , wherein said control section controls the rotational speed of said drawing-up roller by said second driving section according to the rotational speed of said coating roller by said first driving section. The control unit stores an application amount data table holding application amount data, which is data for defining the liquid application conveying speed at which the application amount of the treatment liquid for each type of the recording medium is optimal. with
3. The image forming apparatus according to claim 1, wherein said control unit controls said liquid coating transport speed based on said coating amount data read from said coating amount data table and said image forming transport speed. The control unit controls the liquid application/conveyance speed to decrease as the type of the recording medium allows the treatment liquid to permeate more easily, and controls the liquid application/conveyance speed to decrease as the type of the recording medium makes it more difficult for the treatment liquid to permeate. 4. The image forming apparatus according to claim 3 , wherein the speed is controlled to be faster. A temperature sensor for measuring the temperature of the treatment liquid,
5. The image forming apparatus according to claim 1 , wherein said controller controls said liquid application conveying speed based on said temperature. 6. The image forming apparatus according to claim 5 , wherein said control unit controls said liquid application conveying speed to increase as the temperature of said treatment liquid increases. an image forming apparatus including an image forming unit that forms an image by ejecting liquid droplets while conveying a recording medium;
An image forming system comprising: a treatment liquid applying unit that applies a treatment liquid to the recording medium;
7. An image forming system, wherein the treatment liquid application section and the control section are the treatment liquid application section and the control section according to claim 1 .

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