JP7276702B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, there has been known a liquid application device provided with an application amount changing means for changing the application amount of liquid applied to a recording material on which an image is formed.

For example, Japanese Patent Laid-Open No. 2002-100000 discloses a treatment liquid that changes the application amount (applied amount) of the treatment liquid applied to a sheet (recording material) by a treatment liquid transfer roller according to the liquid absorbency (liquid adhesion characteristic) of the sheet. A coating device (liquid applying device) is disclosed. In this processing liquid applying device, of the processing liquid supplied onto the processing liquid transfer roller, the processing liquid is supplied to the paper by the amount that has passed through the gap between the surface of the processing liquid transfer roller and the wall portion. there is Then, the amount of treatment liquid applied to the paper is changed by moving the wall portion according to the liquid absorbency of the paper and adjusting the gap.

However, with the conventional configuration, there are cases where a desired amount of liquid cannot be applied to the recording material due to changes in the usage environment.

In order to solve the above-described problems, the present invention provides an image forming apparatus comprising a recording material on which an image is formed and an application amount changing means for changing an application amount of liquid applied to the recording material, The application amount changing means changes the application amount by changing the viscosity of the liquid, and the recording material to which the liquid is applied is a recording material before an image is formed, The application amount changing means changes the application amount based on the liquid adhesion property of the recording material, and the liquid adhesion property is the surface roughness of the recording material.

According to the present invention, it is possible to apply a desired amount of liquid to the recording material even under conditions where the viscosity of the liquid changes.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment; FIG. FIG. 2 is a schematic configuration diagram of a coating liquid application unit in the image forming apparatus; 4 is a graph showing the relationship between the viscosity of the coating liquid and the amount applied to the print medium; 4 is a graph showing the relationship between the temperature and viscosity of the coating liquid; 4 is a flow chart showing an example of coating amount control of the coating liquid in the embodiment.

An embodiment in which a liquid applying device according to the present invention is applied to an electrophotographic image forming apparatus will be described below.
In the present embodiment, an electrophotographic image forming apparatus will be described as an example, but an image forming apparatus using other methods such as an inkjet method may be used.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to this embodiment.
Symbols "Y", "C", "M", and "K" in the drawing indicate members for yellow, cyan, magenta, and black, respectively. Also, the conveying path of the printing medium P such as paper, which is the recording material, is indicated by a dashed line.

The print medium P fed from the paper feeder 300 is conveyed to the coating liquid application device 200, and the liquid coating liquid is applied to the surface of the print medium P by the coating liquid application unit 201, which is a liquid application device. be. Note that the method of applying the liquid is not limited to coating, and other methods may be used. The applied coating liquid is dried by heat in the drying section 202 and then conveyed to the image forming apparatus main body 100 .

The image forming apparatus main body 100 includes four toner image forming units 101Y, 101M, 101C, and 101K for forming toner images of yellow, magenta, cyan, and black, respectively. These toner image forming units 101Y, 101M, 101C, and 101K use Y, C, M, and K toners of different colors as image forming substances, but otherwise have the same configuration. The symbols Y, C, M, and K indicating the colors of the toners to be used will be omitted as appropriate.

The image forming apparatus main body 100 includes an intermediate transfer belt 102 as an intermediate transfer member below four toner image forming units 101 . An intermediate transfer unit 103, which is a transfer means, endlessly moves the intermediate transfer belt 102 while being stretched by a plurality of tension rollers. Below the intermediate transfer unit 103, a fixing device 104 as fixing means is provided. The print medium P on which the toner image has been fixed by the fixing device 104 is finally conveyed to the discharge tray 105 .

FIG. 2 is a schematic configuration diagram of a coating liquid applying unit 201 as a liquid applying device according to this embodiment.
Depending on the type of print media, image formation may not be possible because the required fixing strength cannot be obtained. In some cases, a predetermined fixing strength can be obtained by performing this. In this embodiment, in order to cope with such a print medium, the image is printed on the print medium before the fixing process (in this embodiment, the print medium before the image is formed (before the image is transferred)). A predetermined fixing strength is obtained by applying a coating liquid for increasing the fixing strength of (toner).

The coating liquid application unit 201 of this embodiment draws up the coating liquid 1 in the tank by the squeeze roller 2 that is rotationally driven and supplies it onto the application roller 3 . A print medium P transported along a transport path 5 passes through the nip portion between the application roller 3 and the pressure roller 4 , and the coating liquid 1 on the application roller 3 is applied (applied) to the print medium P at that time. ) is done.

At this time, the amount of the coating liquid 1 that adheres to the print medium P (the amount that is applied to the print medium P) is affected by the difference in the liquid adhesion characteristics, such as the material and surface condition of the print medium P. The amount of the coating liquid 1 to be applied (the amount of the coating liquid 1 applied to the print medium P) is different. If the amount of the coating liquid applied to the print medium P is insufficient, the fixing strength improvement effect of the coating liquid 1 may be insufficient, and the desired fixing strength may not be obtained. On the other hand, if the amount of coating liquid applied to the print medium P is excessive, the drying process in the drying unit 202 takes a long time, and the coating liquid 1 is wasted.

Among the liquid adhesion characteristics of the print medium P, the difference in the surface condition of the print medium P in particular causes a difference in the amount of coating liquid adhered to the print medium P (the amount of coating liquid applied to the print medium P). Such a surface state of the print medium P can be grasped by the surface roughness of the print medium P, for example. The relationship between the surface roughness of the print medium P and the coating liquid adhesion amount of the print medium P is such that the coating liquid application amount increases as the surface roughness increases, and conversely, the coating liquid application amount decreases as the surface roughness decreases. There is a relationship that Therefore, for example, when it is desired to apply substantially the same amount of coating liquid 1 to all printing media P regardless of the difference in surface roughness, for printing media P with small surface roughness, The coating amount of the coating liquid 1 is adjusted to be large, and the coating amount of the coating liquid 1 to the printing medium P is adjusted to be small for the printing medium P having a large surface roughness.

Here, for example, means for changing the amount of the coating liquid 1 supplied to the coating roller 3 can be considered as the application amount changing means for changing the amount of the coating liquid 1 to be applied to the printing medium P. According to this application amount changing means, the amount of the coating liquid 1 sent to the nip portion between the application roller 3 for applying the coating liquid 1 to the printing medium P and the pressure roller 4 is changed. The application amount of the coating liquid 1 to is changed.

However, even if the same amount of coating liquid 1 is supplied to the application roller 3, the amount of coating liquid adhered to the print medium P varies depending on the difference in the viscosity of the coating liquid 1. FIG. Specifically, the higher the viscosity of the coating liquid 1, the greater the amount of coating liquid adhered to the printing medium P, and the lower the viscosity of the coating liquid 1, the less the amount of coating liquid adhered to the printing medium P. Therefore, in a situation where the viscosity of the coating liquid 1 changes due to, for example, changes in the usage environment, even if a specified amount of the coating liquid 1 is supplied to the application roller 3, the coating liquid 1 will not be applied to the printing medium P. The application amount may deviate from the desired amount, and the desired amount of the coating liquid 1 may not be adhered to the print medium P.

Therefore, in the present embodiment, viscosity changing means for changing the viscosity of the coating liquid 1 is provided, and the viscosity changing means is used as application amount changing means for changing the amount of the coating liquid 1 applied to the printing medium P. If the viscosity of the coating liquid 1 is increased, the amount of the coating liquid 1 applied to the printing medium P can be increased, and if the viscosity of the coating liquid 1 is decreased, the amount of the coating liquid 1 applied to the printing medium P can be reduced. be able to. Therefore, by changing the viscosity of the coating liquid 1 by the viscosity changing means, the amount of the coating liquid 1 applied to the printing medium P can be changed. Therefore, as described above, when it is desired to apply substantially the same amount of the coating liquid 1 to all printing media P regardless of the difference in surface roughness, the viscosity The viscosity of the coating liquid 1 is increased by the changing means so that the amount of the coating liquid 1 applied to the printing medium P is increased. The viscosity of the coating liquid 1 is lowered so that the amount of the coating liquid 1 applied to the printing medium P is reduced.

The viscosity changing means of this embodiment is temperature changing means for changing the viscosity of the coating liquid 1 by changing the temperature of the coating liquid 1 . However, other viscosity changing means such as means for changing the solid content concentration of the coating liquid 1 may be used. In the case of the temperature changing means, the viscosity of the coating liquid 1 can be lowered by increasing the temperature of the coating liquid 1, and the viscosity of the coating liquid 1 can be increased by decreasing the temperature of the coating liquid 1.

As shown in FIG. 2, the coating liquid applying unit 201 of this embodiment includes a temperature sensor 6 for detecting the temperature of the coating liquid 1, a heater 8 as a heating means for heating the coating liquid 1, and a surface of the printing medium P. A temperature control unit 7 for controlling the heater 8 based on the roughness and the detection result of the temperature sensor 6 is provided. In the present embodiment, the surface roughness of the print medium P is detected by the optical sensor 10 arranged on the upstream side of the transport path 5 from the coating liquid applying unit 201 as shown in FIG. The acquisition method is not limited to this. For example, the surface roughness of the print medium P may be acquired from information (type information of the print medium P, etc.) input by user operation.

The temperature control unit 7 of the coating liquid application unit 201 in the present embodiment first determines the amount of coating liquid applied to the printing medium P based on the surface roughness of the printing medium P obtained from the detection result of the optical sensor 10. A target temperature is determined at which the viscosity of the coating liquid 1 that is appropriate for the roughness is obtained. When the temperature of the coating liquid 1 detected by the temperature sensor 6 is lower than the determined target temperature, the temperature control unit 7 heats the coating liquid 1 with the heater 8 to raise the temperature of the coating liquid 1. Let Conversely, when the temperature of the coating liquid 1 detected by the temperature sensor 6 is higher than the determined target temperature, the cooling fan 11 blows air to the heat sink 9 provided in the tank of the coating liquid 1. , the temperature of the coating liquid 1 is lowered.

By performing such control, the temperature of the coating liquid 1 applied to the print medium P is controlled to the target temperature. The viscosity is controlled so that the amount of liquid applied is appropriate for the surface roughness of the print medium P. By controlling the viscosity of the coating liquid 1 as in this embodiment, if the amount of the coating liquid applied to the printing medium P is adjusted to an appropriate amount according to the surface roughness of the printing medium P, changes in the usage environment can be prevented. An appropriate amount of coating liquid 1 according to the surface roughness of the printing medium P can be applied to the printing medium P even under a situation where the viscosity of the coating liquid 1 changes due to, for example, the printing medium P.

FIG. 3 is a graph showing the relationship between the viscosity η of the coating liquid 1 and the amount applied to the printing medium P. As shown in FIG.
As shown in FIG. 3, the lower the viscosity η of the coating liquid 1, the smaller the amount of the coating liquid 1 applied to the printing medium P. coating amount increases. As described above, the coating amount of the coating liquid 1 tends to increase as the surface roughness of the print medium P increases. Therefore, the target viscosity ηT of the coating liquid 1 is determined by the surface roughness of the print medium P when the target coating amount is Mt.

FIG. 4 is a graph showing the relationship between the temperature and viscosity of the coating liquid 1. As shown in FIG.
As shown in FIG. 4, the higher the temperature of the coating liquid 1 is, the lower the viscosity of the coating liquid 1 is. Conversely, the lower the temperature of the coating liquid 1 is, the higher the viscosity of the coating liquid 1 is. 4, the target temperature KT for obtaining the target viscosity ηT of the coating liquid 1 determined according to the surface roughness of the print medium P is determined.

FIG. 5 is a flow chart showing an example of application amount control of the coating liquid 1 in this embodiment.
In this embodiment, when the temperature control unit 7 acquires the surface roughness of the print medium P detected by the optical sensor 10 (S1), the coating liquid viscosity corresponding to the coating amount target value Mt corresponding to the surface roughness is A target value ηT is calculated (S2). Then, the temperature control unit 7 calculates a coating liquid target temperature KT corresponding to the calculated target coating liquid viscosity ηT (S3). Next, after obtaining the temperature K of the coating liquid 1 detected by the temperature sensor 6 (S4), the temperature control unit 7 compares the temperature K of the coating liquid 1 with the target temperature KT. As a result, when K<KT, the heater 8 performs heating, and when K>KT, the cooling fan 11 blows air to the heat sink 9 . Then, when K=KT, the image forming operation (printing operation) in the image forming apparatus main body 100 is started. The condition for starting printing may be the target temperature KT±N (N: any temperature range).

In this embodiment, the liquid such as the coating liquid 1 is applied to the recording material such as the printing medium P before an image is formed. If so, the same applies even if the liquid is applied to the recording material after the image is formed.
In the present embodiment, the liquid (coating liquid 1) for increasing the fixing strength of the image (toner) on the print medium P is applied to the recording material. It is the same even if it does.

What has been described above is only an example, and each of the following aspects has a unique effect.
[First aspect]
In the first mode, application amount changing means (e.g., temperature control unit 7) for changing the application amount (e.g., application amount) of liquid (e.g., coating liquid 1) to be applied to a recording material (e.g., printing medium P) on which an image is formed. , heater 8, cooling fan 11, etc.), wherein the applied amount changing means changes the applied amount by changing the viscosity of the liquid. It is characterized by
As a result of research by the present inventors, it has been found that the main reason why the desired amount of liquid cannot be applied to the recording material due to changes in the usage environment, etc., is the change in the viscosity of the liquid. That is, when the viscosity of the liquid changes due to changes in the usage environment, etc., the amount of liquid applied to the recording material fluctuates, and the desired amount of liquid may not be applied to the recording material. bottom. According to this aspect, the amount of liquid to be applied to the recording material is changed by changing the viscosity of the liquid. can be given. Therefore, a desired amount of liquid can be applied to the recording material even under conditions where the viscosity of the liquid changes.

[Second aspect]
A second aspect is characterized in that, in the first aspect, the application amount changing means changes the application amount based on the liquid adhesion characteristics (for example, surface roughness) of the recording material.
According to this aspect, it is possible to apply an appropriate amount of liquid to the recording material according to the liquid adhesion characteristics of the recording material. It should be noted that the appropriate amount here may differ depending on the liquid adhesion characteristics of the recording material, or may be the same amount regardless of the liquid adhesion characteristics of the recording material.

[Third aspect]
A third aspect is characterized in that, in the second aspect, the liquid adhesion property is the surface roughness of the recording material.
According to this aspect, it is possible to apply an appropriate amount of liquid to the recording material according to the surface roughness of the recording material. It should be noted that the appropriate amount here may vary depending on the surface roughness of the recording material, or may be the same amount regardless of the surface roughness of the recording material.

[Fourth aspect]
A fourth aspect is characterized in that, in the third aspect, the surface roughness is measured by an optical sensor (for example, optical sensor 10).
According to this aspect, the surface roughness of the recording material can be obtained with a simple configuration.

[Fifth aspect]
According to a fifth aspect, in any one of the second to fourth aspects, the applied amount changing means changes the viscosity so that a difference in the applied amount of the liquid between recording materials having different liquid adhesion characteristics becomes small. It is characterized by
According to this aspect, substantially the same amount of liquid can be applied to the recording material even if the liquid adhesion characteristics of the recording material are different.

[Sixth aspect]
A sixth aspect is characterized in that, in any one of the first to fifth aspects, the recording material to which the liquid is applied is a recording material before an image is formed.
This aspect can be applied to a configuration in which liquid is applied to a recording material before an image is formed.

[Seventh aspect]
According to a seventh aspect, in any one of the first to sixth aspects, the application amount changing means changes the viscosity of the liquid by changing the temperature of the liquid.
According to this aspect, the viscosity of the liquid can be changed with a simple configuration.

[Eighth aspect]
An eighth aspect is an image forming apparatus comprising the liquid applying device according to any one of the first to seventh aspects.
It is possible to realize an image forming apparatus that applies just the right amount of liquid to a recording material even under conditions where the viscosity of the liquid changes.

Reference Signs List 1: Coating liquid 2: Squeeze roller 3: Application roller 4: Pressure roller 5: Conveyance path 6: Temperature sensor 7: Temperature control unit 8: Heater 9: Heat sink 10: Optical sensor 11: Cooling fan 100: Main body of image forming apparatus 101: Toner Image Forming Section 102: Intermediate Transfer Belt 103: Intermediate Transfer Unit 104: Fixing Device 105: Discharge Tray 200: Coating Liquid Application Device 201: Coating Liquid Application Unit 202: Drying Section 300: Paper Feed Device P: Print Media

JP 2010-194526 A

Claims (7)

An image forming apparatus comprising: a recording material on which an image is formed; and an application amount changing means for changing an application amount of liquid applied to the recording material,
The application amount changing means changes the application amount by changing the viscosity of the liquid,
the recording material to which the liquid is applied is a recording material before an image is formed;
The application amount changing means changes the application amount based on the liquid adhesion characteristics of the recording material,
The image forming apparatus , wherein the liquid adhesion property is surface roughness of the recording material . The image forming apparatus according to claim 1 ,
An image forming apparatus comprising an optical sensor for measuring the surface roughness. The image forming apparatus according to claim 1 or 2 ,
The image forming apparatus, wherein the applied amount changing unit changes the viscosity so that a difference in applied amount of the liquid between recording materials having different liquid adhesion characteristics is reduced. An image forming apparatus comprising: a recording material on which an image is formed; and an application amount changing means for changing an application amount of liquid applied to the recording material,
The application amount changing means changes the application amount by changing the viscosity of the liquid,
the recording material to which the liquid is applied is a recording material before an image is formed;
The application amount changing unit changes the viscosity based on the liquid adhesion properties of the recording materials so that a difference in the liquid application amount between recording materials having different liquid adhesion properties becomes small. forming device. The image forming apparatus according to any one of claims 1 to 4 ,
The image forming apparatus, wherein the applied amount changing means changes the viscosity of the liquid by changing the temperature of the liquid. An image forming apparatus comprising: a recording material on which an image is formed; and an application amount changing means for changing an application amount of liquid applied to the recording material,
The application amount changing means changes the application amount by changing the viscosity of the liquid,
the recording material to which the liquid is applied is a recording material before an image is formed;
The image forming apparatus, wherein the applied amount changing means changes the viscosity of the liquid by changing the temperature of the liquid. The image forming apparatus according to claim 6,
The image forming apparatus, wherein the applied amount changing means changes the applied amount based on the liquid adhesion property of the recording material.

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