KR100354736B1 - Image forming method and image forming device of a wet-typed printer using the same - Google Patents

Abstract

An image forming method and an image forming apparatus for a wet printer using the same are described. An image forming method includes: an initial positioning step of placing a developing roller and a squeeze roller of a unit developing unit at a first position spaced a predetermined distance from the photosensitive belt; A squeeze roller raising step of sequentially raising the squeeze rollers of the unit developing parts to a second position so that each squeeze roller contacts the photosensitive belt with a first pressure; A raising step of raising a developing roller to a third position; An image forming step of supplying a developing solution between the developing roller and the photosensitive belt to develop an electrostatic latent image formed on the photosensitive belt into a toner image; A developing roller returning step of returning the developing rollers of the unit developing units in the third position to the first position; And a squeeze roller returning step of returning the squeeze rollers of the unit developing units at the second position to the first position. Therefore, the present invention can lower the power of the driving unit of the developing unit and prevent damage of the photosensitive belt when the drip line is removed.

Description

Image forming method and image forming device of a wet-typed printer using the same}

The present invention relates to an image forming method and an image forming apparatus for a wet printer using the same.

The image forming apparatus is roughly divided into wet and dry depending on the type of developer used. The wet image forming apparatus uses a developer in which powder toner is dispersed in a volatile liquid carrier, and applies a photosensitive belt that circulates an endless orbit image as a medium for image formation.

1 shows a schematic configuration of a conventional image forming apparatus.

Referring to FIG. 1, the photosensitive belt 110 is supported by three rollers 111, 112, and 113. Among the three rollers, reference numeral 111 denotes a backup roller. The toner image formed on the photosensitive belt is pressurized to a certain pressure by the photosensitive belt 110 to the transfer roller 114 installed adjacent thereto. It is to be transferred to. One side of the transfer roller 114 is provided with a pressure roller 115 in contact with the transfer roller 114 at a constant pressure to transfer the recording paper 116 between the transfer roller 114 and the pressure roller 115. The toner image attached to the roller 114 is to be transferred.

An image forming apparatus 200 for forming a toner image on the surface of the photosensitive belt 110 is provided in the transfer section of the photosensitive belt 110 between the steering roller 112 and the driving roller 113. The image forming unit 200 includes an LSU (Line Scanning Unit, 202a, 202b, 202c, 202d) and a developing unit 201a, 201b, 201c, and 201d which are alternately installed. One LSU and a developing unit adjacent to each other form a group to form a unit toner image for each color (Yellow, Magent, Cyan, Black).

The LSUs 202a, 202b, 202c, and 202d form an electrostatic latent image by irradiating a photosensitive surface of the photosensitive belt 110 with a laser beam according to color image signals, and developing units 201a, 201b, 201c, and 201d. Develops an electrostatic latent image formed by LSUs (Line Scanning Units) into a toner image.

The developing units 201a, 201b, 201c, and 201d of the developing apparatus 200 as described above remove the excess amount of the developer applied to the photosensitive belt 110 and the developing roller applied to the photosensitive belt 110. A squeeze roller is provided.

Referring to FIG. 2, the developing parts 201a, 201b, 201c, and 201d may be formed on the upper side of the container 302 storing the developing solution 301, while maintaining a predetermined distance from the photosensitive belt 110 during development. Is applied by the developing roller 205 and the developing roller 205 to apply the developing solution 301 from the developing solution supply device 300 provided on the photosensitive belt 110 to contribute to the development of the toner image and to retain the remaining excess developer. By removing the squeeze roller 204 is provided in contact with the photosensitive belt 110 at a predetermined pressure. The cleaning roller 206 in contact with the development roller 205 is located under the developing roller 205, and the cleaning blade separating the developer attached to the surface of the squeeze roller 204 under the squeeze roller 204. 207 is located. In addition, a backup roller 116 is positioned above the photosensitive belt 110 opposite to the squeeze roller 204. The backup roller 116 supports the back when the squeeze roller 204 is in contact with the photosensitive belt 110.

The developing parts having the structure as described above are maintained as shown in FIG. 2 when the image is formed, and are separated from the photosensitive belt 110 when the idle time, that is, the image forming is not in progress, thus, the image At the time of formation, the phenomenon rollers having a predetermined gap on the photosensitive belt are spaced at even larger intervals, and the squeeze rollers that are in contact with the photosensitive belt are separated. To this end, the developing unit is provided with a lifting device. At this time, the developing parts are lifted up and down simultaneously by one lifting device, or are lifted up and down in two separated states by two separate lifting devices.

On the other hand, the squeeze roller which is raised and lowered together with the developing part by the elevating device is installed to be able to be moved up and down elastically in the developing part, and is in contact with the photosensitive belt at different pressure. This squeeze roller not only squeezes the excess in the developer attached to the photosensitive belt when developing the electrostatic latent image into the toner image, but also removes the so-called drip lines formed on the photosensitive belt after development. To this end, in the squeegeeing step, the squeeze roller rotates in the direction in which the photosensitive belt proceeds in contact with the photosensitive belt at high pressure, and when the drip line is removed, the squeeze roller proceeds in contact with the low pressure. Remove the drip line by rotating it in the reverse direction. The drip line is formed by developing a developer solution interposed therebetween at a high height when the developing roller close to the photosensitive belt is spaced apart from the photosensitive belt. It demonstrates in detail, referring.

3A shows a state of an idle period during which image formation is not performed, that is, a state of an initial position, in which developing units 201a, 201b, 202c, and 202d maintain a constant distance from the photosensitive belt 110. The developing rollers 205a, 205b, 205c and 205d and the squeeze rollers 204a, 204b, 204c and 204d provided in the developing units 201a, 201b, 202c and 202d are spaced apart from the photosensitive belt.

FIG. 3B shows a state in which the squeeze rollers 204a, 204b, 204c, and 204d are first contacted with the photosensitive belt 110 at a high pressure in preparation of image formation. If ((204a, 204b, 204c, 204d) is located, no drip line removal operation occurs because no image formation is performed at this time.

3C shows a state in which image formation is being performed, and the development rollers 201a, 201b, 202c, and 202d and the developer supply apparatuses 300a, 300b, 300c, and 300d are raised. In this state, exposure to the image forming region of the photosensitive belt by the LSUs corresponding to each of the developing portions 201a, 201b, 202c, and 202d is performed, followed by supplying the developing solution from the developing solution supply apparatuses. Application of the developer 301 to the image forming area is performed by the 201a, 201b, 202c, and 202d. The developer-coated portion is squeezed while passing through the squeeze rollers 204a, 204b, 204c, and 204d to remove excess from the developer attached to the photosensitive belt 110.

3D shows the state of the drip line removal position after image formation is completed, and the developing rollers 201a, 201b, 202c, and 202d and the developer supply apparatuses 300a, 300b, 300c, and 300d are lowered, and the developing roller 201a is shown. , 201b, 202c, and 202d show a state away from the photosensitive belt 110. In this process, the developing solution 301 intervened between the photosensitive belt 110 and the developing rollers 201a, 201b, 202c, and 202d is agglomerated on the surface of the photosensitive belt 110, thereby causing a drip line (e.g. 301a) is formed. At this time, the squeeze rollers 204a, 204b, 204c, and 204d in contact with the photosensitive belt 110 are rotated in reverse to remove the drip line 301a.

4 is a time chart illustrating the operation of the developing roller and the squeeze rollers operated as described above.

Referring to FIG. 4, section A shows the initial position (home position), that is, the state of FIG. 3A, wherein all squeeze rollers 204a, 204b, 204c, and 204d and the development rollers 201a, 201b, 202c, and 202d are shown. Shows that they are descending. At this time, the squeeze rollers 204a, 204b, 204c, and 204d and the development rollers 201a, 201b, 202c, and 202d are spaced apart from each other by about 4 mm with respect to the photosensitive belt 110. Section B shows the drip line removal position, that is, the state of FIGS. 3B and 3D, in which only the squeeze rollers 204a, 204b, 204c, and 204d are simultaneously raised to a low pressure (generally 2kgf) on the photosensitive belt 110. Show contact. Then, the section C shows the image forming position, that is, the state at Fig. 3C, and the squeeze rollers 204a, 204b, 204c, and 204d rise further (actually no longer rise), and the development roller 201a , 201b, 201c, and 201d are sections in which image formation is performed in a state where the photosensitive belt 110 is disposed at a predetermined interval.

The problem with the conventional apparatus for forming an image through the above process is that each group of all squeeze rollers and developing rollers are operated simultaneously as shown in FIGS. 3B and 3C and in sections B and C of FIG. 4. Therefore, the load on the driving device for operating it is large, and therefore, a driving device having a power enough to overcome this is to be provided. In addition, by using a drive device having such a strong power, the material on the power transmission system from the drive device has to be used with a material of a high strength enough to overcome the load from the drive device. Parts prices will rise.

In addition, another problem of the conventional apparatus is that some squeeze rollers are in contact with the image forming region of the photosensitive belt 110 when the drip line is removed. Is that it can be damaged. 3D illustrates that the first image forming unit 201a is in contact with the non-image forming region 110a of the photosensitive belt 110 and the squeeze rollers 204b, 204c, and 204d of the remaining developing units 201b, 202c, and 202d are exposed to light. The state in contact with the image forming area of the belt 110 is shown. Such a state is indicated by the fact that the respective development rollers of the image forming units are simultaneously lowered, and the damage of the image forming region means the physical damage of the photosensitive belt.

The present invention has a first object to provide an image forming method capable of lowering the power of a driving device for raising and lowering a developing roller and a squeeze roller of a developing unit, and an image forming apparatus for a wet printer using the same.

It is a second object of the present invention to provide an image forming method capable of preventing damage to a photosensitive belt when removing a drip line, and an image forming apparatus for a wet printer using the same.

A third object of the present invention is to provide an image forming method capable of suppressing contamination of a developer by removing drip lines by color, and an image forming apparatus of a wet printer using the same.

The fourth object of the present invention is to provide an image forming method capable of reducing the cost of a product by unifying a driving source for a developing roller and a squeeze roller of a developing unit, and an image forming apparatus of a wet printer using the same.

A fifth object of the present invention is to provide an image forming apparatus for a wet printer, in which a material having a lower mechanical strength can be used as compared with the related art, in which manufacturing cost is reduced.

1 shows a schematic configuration of a conventional image forming apparatus.

2 is a schematic configuration diagram of a unit developing unit of a conventional image forming apparatus;

3A to 3D illustrate an image forming process by a conventional image forming apparatus;

4 is a time chart showing the operation of the development roller and the squeeze roller of the conventional image forming apparatus;

5 is a schematic configuration diagram of a unit developing unit of an image forming apparatus to which an image forming method of the present invention is applied;

6a to 6f are views showing the operation of the developing roller and the squeeze roller of the developing unit according to the first embodiment of the image forming method of the present invention;

7A to 7K are views showing the operation of the developing roller and the squeeze roller of the developing unit according to the second embodiment of the image forming method of the present invention;

8 is a schematic structural diagram of a unit developing unit applied to Embodiment 1 according to the image forming apparatus of the present invention;

9 is a schematic plan view of a cam slider for driving a squeeze roller of a unit developing unit in the image forming apparatus of the present invention;

10A to 10H are diagrams for explaining step-up states of the squeeze roller by the cam slider shown in FIG. 9;

11 is a schematic structural diagram of a unit developing unit applied to Embodiment 2 according to the image forming apparatus of the present invention;

12 is a schematic plan view of a cam slider for driving the squeeze roller of the unit developing part of the second embodiment according to the image forming apparatus of the present invention;

13 is a time chart showing the operation of the developing roller, the squeeze roller, and the cleaning blade according to the second embodiment of the image forming apparatus of the present invention.

In order to achieve the above object, according to the present invention, a developing roller is applied to a photosensitive belt having a non-image forming area by moving a developer of a predetermined color supplied by a developer supplying device of a wet printer, and the photosensitive belt. An image forming method using a wet printer having a plurality of unit developing parts including; a squeeze roller for removing an excess of developer from a developer supplied thereto, wherein the developing rollers and squeeze rollers of all the unit developing parts are predetermined from the photosensitive belt. An initial positioning step of positioning the first location spaced apart from each other; The squeeze rollers of the unit developing parts arranged in the traveling direction of the photosensitive belt are sequentially raised to the second position, and the squeeze rollers are sequentially raised in the reverse order of the traveling direction of the photosensitive belt, so that each squeeze roller is made with respect to the photosensitive belt. A squeeze roller raising step of contacting at one pressure; A developing roller raising step of raising the developing rollers to a third position so that the developing rollers of the unit developing units are positioned at a predetermined interval on the photosensitive belt, and sequentially raising the developing rollers in the reverse order of the traveling direction of the photosensitive belt. ; An image for developing an electrostatic latent image formed on the photosensitive belt as a toner image by supplying a developer solution between the developing roller and the photosensitive belt in a state where at least one of the squeeze rollers and the developing roller is located at the second position and the third position, respectively. Forming step; A developing roller returning step of returning the developing rollers of the unit developing units in the third position to the first position, and sequentially lowering the developing rollers in the order of traveling direction of the photosensitive belt; And returning the squeeze rollers of the unit developing units at the second position to the first position, and returning the squeeze rollers to sequentially lower the developing rollers in the order of the traveling direction of the photosensitive belt. do.

In the method of the present invention, it is preferable that each of the squeeze rollers and the development rollers of each unit developing unit is moved up and down with a time difference. In addition, the developing roller rising step may further include a pressure increasing step for allowing the squeeze roller to be contacted at a second pressure higher than the contact pressure of each squeeze roller to the photosensitive belt in the rising step of the squeeze roller. In the returning step, it is preferable to further include reducing the contact pressure of the squeeze roller in contact with the photosensitive belt with the second pressure to the first pressure.

Further, in the squeeze roller rising step, it is preferable that the squeeze roller of the second position in contact with the photosensitive belt is rotated in the direction in which the photosensitive belt proceeds.

In the image forming step, the developing roller and the squeeze rollers are preferably rotated in the advancing direction of the photosensitive belt.

Further, according to another type of image forming method of the present invention, a developing roller is applied to a photosensitive belt having a non-image forming region by moving a developer of a predetermined color supplied by a developer supplying device of a wet printer in one direction. An image forming method using a wet printer having a plurality of unit developing parts including a squeeze roller for removing an excess of developer from a belt supplied developer, wherein the developing rollers and squeeze rollers of all the unit developing parts are predetermined from the photosensitive belt. An initial positioning step of positioning the first location spaced apart from each other; The squeeze rollers of the unit developing parts arranged in the traveling direction of the photosensitive belt are sequentially raised to the second position, and the squeeze rollers are sequentially raised in the reverse order of the traveling direction of the photosensitive belt, so that each squeeze roller is made with respect to the photosensitive belt. A squeeze roller raising step of contacting at one pressure; A developing roller raising step of raising the developing rollers to a third position so that the developing rollers of the unit developing units are positioned at a predetermined interval on the photosensitive belt, and sequentially raising the developing rollers in the reverse order of the traveling direction of the photosensitive belt. ; An image for developing an electrostatic latent image formed on the photosensitive belt as a toner image by supplying a developer solution between the developing roller and the photosensitive belt in a state where at least one of the squeeze rollers and the developing roller is located at the second position and the third position, respectively. Forming step; A return step of returning the developing rollers of the unit developing units at the third position to the first position, wherein the developing rollers sequentially descend the developing rollers in the order of traveling direction of the photosensitive belt; A drip line removing step of removing a drip line formed when the developing roller is separated from the photosensitive belt while rotating the squeeze roller contacted with the photosensitive belt at a predetermined pressure in a reverse direction to the traveling direction of the photosensitive belt; And returning the squeeze rollers of the unit developing units at the second position to the first position, and returning the squeeze rollers to sequentially lower the developing rollers in the order of the traveling direction of the photosensitive belt. do.

In the developing roller returning step of the image forming method of the present invention, each developing roller of the unit developing units returns to the first position when the non-image forming region of the photosensitive belt is positioned thereon. It is preferable that a drip line formed in the photosensitive belt is generated in the non-image forming region of the photosensitive belt as the respective developing rollers descend.

In the method of the present invention, it is preferable that each of the squeeze rollers and the development rollers of each unit developing unit is moved up and down with a time difference. In addition, the developing roller rising step may further include a pressure increasing step for allowing the squeeze roller to be contacted at a second pressure higher than the contact pressure of each squeeze roller to the photosensitive belt in the rising step of the squeeze roller. In the returning step, it is preferable to further include reducing the contact pressure of the squeeze roller in contact with the photosensitive belt with the second pressure to the first pressure.

Further, in the squeeze roller rising step, it is preferable that the squeeze roller of the second position in contact with the photosensitive belt is rotated in the direction in which the photosensitive belt proceeds.

In the image forming step, the developing roller and the squeeze rollers are preferably rotated in the advancing direction of the photosensitive belt.

In order to achieve the above object, according to the present invention, the developing roller is applied to the photosensitive belt having a non-image forming area by moving the developer of a predetermined color supplied by the developer supplying device of the wet printer in one direction, and the photosensitive belt supply A squeeze roller for removing excess developer from the developed developer; A main frame supporting the developing roller; A subframe in which the squeeze roller is elastically supported vertically and supported by the main frame in a descending manner; A plurality of unit developing units provided; A main frame elevating device for elevating the main frames of the unit developing units; A subframe elevating device for elevating the subframe with respect to the mainframe; In the image forming apparatus of the wet printer, wherein the sub-frame lifting device is moved up and down step by step to the first position of the base, the second position in the middle and the third position of the upper by interfering the subframe, When the subframe is raised, the subframes of the unit developing units are sequentially raised in the reverse order of the feeding direction of the photosensitive belt, and when the subframe is lowered, the unit developing units of the unit developing units are transferred in the feeding direction of the photosensitive belt. And descending the subframes sequentially, wherein the mainframe elevating device interferes with the mainframe to raise and lower the first frame to a second position higher than the first position, and to raise the mainframe. In order to sequentially raise the main frames of the unit phenomena in the reverse order of the conveyance direction of the photosensitive belt, when the main frame is lowered, That the transport direction of the light belts, which is configured to sequentially lowered in the sub-frame of the developing unit of the image forming apparatus is parts of a liquid printer is provided.

In the image forming apparatus of the present invention, it is preferable that each of the squeeze rollers and the developing rollers of the unit developing portions are moved up and down with a time difference. In addition, the squeeze roller is in contact with the photosensitive belt in the second position and the third position, it is preferable that the contact pressure of the squeeze roller to the photosensitive belt in the third position is higher than the contact pressure in the second position. .

In addition, the squeeze roller is preferably such that when the sub-frame is lowered from the third position to the second position, the squeeze roller rotates in the opposite direction to the direction in which the photosensitive belt travels.

When the subframe is in the third position, the developing roller and the squeeze rollers are preferably rotated in the advancing direction of the photosensitive belt.

In the image forming apparatus of the present invention, the main frame elevating device and the subframe elevating device are provided with a cam stud in each of the main frame and the sub frames of the unit developing units, and each of the cam studs is provided in one cam slider. The guide is preferably provided by a plurality of cam grooves for determining the first position and the second position of the main frame, the first position, the second position and the third position of the subframe.

The unit developing unit may further include: a subframe to which the squeeze roller is rotatably mounted; A main frame in which the subframe is supported to move up and down a predetermined distance; A compression spring supporting the subframe from below to provide an elastic lifting force to the subframe; A supporter for supporting a lower portion of the spring; Preferably, the supporter is provided with respect to the main frame, and the supporter is provided with a cam stud guided to the cam groove of the cam slider.

In the image forming apparatus of the present invention, it is preferable that a cam stud guided to a cam groove provided in the cam slider is provided on the main frame, and further provided on the cam slider to guide the cam stud of the supporter. The cam groove is preferably formed to have the position of the three supporters different in height from each other.

Hereinafter, with reference to the accompanying drawings, it will be described in detail preferred embodiments according to the image forming method of the present invention and the image forming apparatus for a wet printer to which the same is applied.

Image Formation Method

5 shows a schematic structure of a unit developing unit of an image forming apparatus to which the image forming method of the present invention is applied. The developer (301Y, 301M, 301C, 301K) of the corresponding color is stored in the developing solution containers (302Y, 302M, 302C, 302K) of the yellow, magenta, cyan, and black developing parts (201Y, 201M, 201C, and 201K). At the upper part thereof, developing rollers 205Y, 205M, 205C, and 205K and squeeze rollers 204Y, 204M, 204C, and 204K are arranged in the traveling direction of the photosensitive belt 110, and each developing roller 205Y and 205M is provided. , 205C, 205K are provided with cleaning rollers 206Y, 206M, 206C, and 206K, and squeeze roller cleaning blades 207Y, 207M, 207C, and 207K are provided at each lower portion of the squeeze rollers 204Y, 204M, 204C, and 204K. ) Is installed.

Each of the developing units 201Y, 201M, 201C, and 201K having the above-described structure are disposed at a predetermined interval in the traveling direction of the photosensitive belt 110, and corresponding to one side of each of the developing units 201Y, 201M, 201C, 201K. The developer supply devices 300Y, 300M, 300C, and 300K are provided to supply the developer 301Y, 301M, 301C, and 301K of color.

Embodiment 1 of the image forming method

Embodiment 1 of the shaping method of the present invention by the developing unit configured as described above has the following steps.

A) The developing rollers 301Y, 301M, 301C and 301K of all the unit developing units 201Y, 201M, 201C and 201K and the squeeze rollers 204Y, 204M, 204C and 204K are positioned in the first initial position.

B) Raise the squeeze rollers 204Y, 204M, 204C, 204K of the developing rollers 205Y, 205M, 205C, 205K arranged in the traveling direction of the photosensitive belt 110 to a second position higher than the first position. , The squeeze rollers 204Y, 204M, 204C, and 204K of the developer tanks 302Y, 302M, 302C, and 302K are sequentially raised in the reverse order of the direction of the photosensitive belt 110 to squeeze rollers 204Y, 204M, and 204C. , 204K) the squeeze roller ascending step of contacting the photosensitive belt 110 at a first pressure.

C) The developing rollers 205Y, 205M, 205K, so that the developing rollers 205Y, 205M, 205C, 205K of the unit developing units 201Y, 201M, 201C, and 201K are positioned at predetermined intervals on the photosensitive belt 110. Raising step 205C, 205K to the third position, the phenomenon in order to raise the development rollers (205Y, 205M, 205C, 205K) sequentially in the reverse order of the direction of the photosensitive belt (110).

D) The squeeze rollers 204Y, 204M, 204C, 204K and the development rollers 205Y, 205M, 205C, 205K of at least one of the developing parts 201Y, 201M, 201C, and 201K are respectively positioned in the second position and the first position. The toner is formed in the photosensitive belt 110 by supplying the developing solution 301Y, 301M, 301C, and 301K between the developing rollers 205Y, 205M, 205C, and 205K and the photosensitive belt 110 while being positioned at the 3 position. An image forming step of developing into an image.

E) The developing rollers 205Y, 205M, 205C, and 205K of the unit developing units 201Y, 201M, 201C, and 201K in the third position are returned to the first position, and the traveling direction of the photosensitive belt 110 is Returning to the developing rollers, the developing rollers 205Y, 205M, 205C, and 205K are sequentially lowered in order.

F) returning the squeeze rollers 204Y, 204M, 204C, and 204K of the unit developing units 201Y, 201M, 201C, and 201K in the second position to the first position, in the order of traveling direction of the photosensitive belt; The squeeze roller returning step of sequentially descending the rollers 205Y, 205M, 205C, and 205K.

6 is a diagram showing the above steps in that order.

FIG. 6A shows a state in which the developing rollers 205Y, 205M, 205C, 205K and the squeeze rollers 204Y, 204M, 204C, and 204K of all the developing parts 201Y, 201M, 201C, and 201K are located in the first position.

6B illustrates that the squeeze roller 204K of the first developing unit 201K is raised to the second position in the reverse order of the traveling direction of the photosensitive belt 110 to contact the photosensitive belt 110 at a predetermined pressure (first pressure). Seems to be

6C shows that the developing roller 205K of the first developing unit 201K and the squeeze roller 204C of the second developing unit 201C are moved to the second position and the third position in the reverse order of the traveling direction of the photosensitive belt 110. Each rises and shows a state in which the photosensitive belt 110 is in contact with a predetermined pressure.

6D shows that the developing roller 205C of the second developing unit 201C and the squeeze roller 204M of the third developing unit 201M move to the third position and the second position in the reverse order of the traveling direction of the photosensitive belt 110. Ascends and shows a state in contact with the photosensitive belt 110 at a predetermined pressure.

6E shows that the developing roller 205M of the third developing unit 201M and the squeeze roller 204Y of the fourth developing unit 201Y move to the second position and the third position in the reverse order of the traveling direction of the photosensitive belt 110. Ascends and shows a state in contact with the photosensitive belt 110 at a predetermined pressure.

6F shows a state in which the developing roller 205K of the fourth developing part 201Y is raised to the third position in contact with the photosensitive belt 110 at a predetermined pressure in the reverse order of the traveling direction of the photosensitive belt 110.

In the above description, the position at which the squeeze rollers 204Y, 204M, 204C, and 204K rise is the second position and the position at which the developing rollers 205Y, 205M, 205C, and 205K rise to the third position, which is a squeeze roller. Although (204Y, 204M, 204C, 204K) and the development rollers 205Y, 205M, 205C, and 205K each operate well and do not appear well in the drawing, they are separately described because they may have a slight height difference.

As shown in FIG. 6F, all of the squeeze rollers 204Y, 204M, 204C, and 204K and the developing rollers 205Y, 205M, 205C, and 205K are raised to the electrostatic latent image formed on the photosensitive belt 110. The process is done in the usual order. After the development process is completed, the reverse order occurs. That is, in the order of the state of FIG. 6A to FIG. 6F is returned.

In the method of the present invention, it is preferable that each of the squeeze rollers and the development rollers of each unit developing part is moved up and down with a time difference as described above. It is also preferable that the squeeze roller of the developing part be brought into contact with the second pressure higher than the first pressure of each squeeze roller against the photosensitive belt when the developing roller of the developing part rises to the third position. In general, the squeeze rollers are supported by a spring, so that the pressure can be increased by further increasing the compression force on the spring. In addition, it is preferable to reduce the contact pressure of the squeeze roller contacting the photosensitive belt with the second pressure to the first pressure when the developing roller of one of the developing parts returns to the first position. The squeeze roller raised to the second position is preferably rotated in the direction in which the photosensitive belt proceeds. In addition, it is preferable that the developing roller and the squeeze rollers are rotated in the advancing direction of the photosensitive belt when both the developing roller and the squeeze roller of the developing part are raised.

The image forming method of the present invention as described above is different from the prior art in that the squeeze rollers 204Y, 204M, 204C, and 204K and the development rollers 205Y, 205M, 205C, and 205K are operated in a sequential order without operating at a time. It has its features. According to this sequential operation, the power, that is, the required torque, of the driving source of the elevating device for raising and lowering the squeeze rollers 204Y, 204M, 204C, and 204K and the developing rollers 205Y, 205M, 205C, and 205K is reduced. That is, the power of the driving source is greatly reduced as compared with the conventional developing method because the rollers 205Y, 205M, 205C, and 205K and the squeeze rollers 204Y, 204M, 204C, and 204K are partially raised and lowered at one time. Will be heard.

Embodiment 2 of the image forming method

Embodiment 2 of the shaping | molding method of this invention by the developing part comprised as mentioned above has the following steps.

A) placing the developing rollers (205Y, 205M, 205C, 205K) and squeeze rollers (204Y, 204M, 204C, 204K) of all the unit developing units (201Y, 201M, 201C, 201K) in the first position.

B) Raise the squeeze rollers 204Y, 204M, 204C, 204K of the developing rollers 205Y, 205M, 205C, 205K arranged in the traveling direction of the photosensitive belt 110 to a second position higher than the first position. , The squeeze rollers 204Y, 204M, 204C, and 204K of the developer bottles 302Y, 302M, 302C, and 302K are sequentially raised in the reverse order of the traveling direction of the photosensitive belt 110, and the respective squeeze rollers 204Y, 204M, and 204C. , 204K) the squeeze roller ascending step of contacting the photosensitive belt 110 at a first pressure.

C) The developing rollers 205Y, 205M, 205K, so that the developing rollers 205Y, 205M, 205C, 205K of the unit developing units 201Y, 201M, 201C, and 201K are positioned at predetermined intervals on the photosensitive belt 110. Raising step 205C, 205K to the third position, the phenomenon in order to raise the development rollers (205Y, 205M, 205C, 205K) sequentially in the reverse order of the direction of the photosensitive belt (110).

D) The squeeze rollers 204Y, 204M, 204C, 204K and the development rollers 205Y, 205M, 205C, 205K of at least one of the developing parts 201Y, 201M, 201C, and 201K are respectively positioned in the second position and the first position. The toner is formed in the photosensitive belt 110 by supplying the developing solution 301Y, 301M, 301C, and 301K between the developing rollers 205Y, 205M, 205C, and 205K and the photosensitive belt 110 while being positioned at the 3 position. An image forming step of developing into an image.

E) The developing rollers 205Y, 205M, 205C, and 205K of the unit developing units 201Y, 201M, 201C, and 201K in the third position are returned to the first position, and the traveling direction of the photosensitive belt 110 is Returning to the developing rollers, the developing rollers 205Y, 205M, 205C, and 205K are sequentially lowered in order.

F) Developing rollers 205Y, 205M, 205C, and 205K while rotating the squeeze rollers 204Y, 204M, 204C, and 204K in contact with the photosensitive belt 110 at a predetermined pressure in the opposite direction to the traveling direction of the photosensitive belt 110. Drip line removal step of removing the drip line formed when the separation from the photosensitive belt (110).

G) Return the squeeze rollers 204Y, 204M, 204C, and 204K of the unit developing units 201Y, 201M, 201C, and 201K in the second position to the first position, in the order of traveling direction of the photosensitive belt. A squeeze roller returning step of sequentially descending the developing rollers (205Y, 205M, 205C, and 205K).

In Embodiment 2 of the image forming method of the present invention, each of the squeeze rollers 204Y, 204M, 204C, and 204K of each of the developing units 201Y, 201M, 201C, and 201K and the development rollers 205Y, 205M, 205C, 205K) is preferably raised and lowered with a parallax. In addition, when the developing roller of any one of the developing portion is raised, it is preferable that the squeeze roller of the developing portion further includes a pressure increasing step to contact the photosensitive belt 110 at a second pressure higher than the first pressure, the drip line removing step In the case, it is preferable to further include the step of reducing the contact pressure of the squeeze roller in contact with the photosensitive belt at a second pressure to the first pressure.

Preferably, the squeeze roller raised to the second position is rotated in a direction in which the photosensitive belt proceeds. In the image forming step, the developing rollers 205Y, 205M, 205C, of the developing units 201Y, 201M, 201C, and 201K are formed. 205K) and the squeeze rollers 204Y, 204M, 204C, and 204K are preferably rotated in the advancing direction of the photosensitive belt 110.

7 is a diagram showing the above steps in that order.

FIG. 7A shows a state in which the developing rollers 205Y, 205M, 205C, and 205K and the squeeze rollers 204Y, 204M, 204C, and 204K of all the developing units 201Y, 201M, 201C, and 201K are positioned in the first position.

FIG. 7B illustrates that the squeeze roller 204K of the first developing unit 201K rises to the second position in the reverse order of the traveling direction of the photosensitive belt 110 to contact the photosensitive belt 110 at a predetermined pressure (first pressure). It shows a state in which the photosensitive belt 110 is rotated in the progressed state.

7C shows that the developing roller 205K of the first developing unit 201K and the squeeze roller 204C of the second developing unit 201C are moved to the second position and the third position in the reverse order of the traveling direction of the photosensitive belt 110. As shown in FIG. 2, the photosensitive belt 110 is rotated in a direction in which the photosensitive belt 110 moves in the state in which each of the up and down contacts the photosensitive belt 110 at a predetermined pressure. At this time, the third position of the squeeze roller 204C has the same height difference with respect to the second position and the first position, except that the contact pressure with respect to the photosensitive belt 110 is higher than the second position.

7D shows that the developing roller 205C of the second developing unit 201C and the squeeze roller 204M of the third developing unit 201M move to the third position and the second position in the reverse order of the traveling direction of the photosensitive belt 110. As shown in the rising state in contact with the photosensitive belt 110 at a predetermined pressure, the photosensitive belt 110 is rotated in the direction of travel.

7E shows that the developing roller 205M of the third developing unit 201M and the squeeze roller 204Y of the fourth developing unit 201Y move to the second position and the third position in the reverse order of the traveling direction of the photosensitive belt 110. As shown in the rising state in contact with the photosensitive belt 110 at a predetermined pressure, the photosensitive belt 110 is rotated in the direction of travel.

7F illustrates the photosensitive belt in a state in which the developing roller 205K of the fourth developing part 201Y is raised to the third position in contact with the photosensitive belt 110 at a predetermined pressure in the reverse order of the traveling direction of the photosensitive belt 110. It shows a state in which the 110 is rotated in the direction of progress.

In the above steps, when both the developing roller and the squeeze roller of one developing part are raised, the squeeze roller of the developing part contacts the photosensitive belt at a pressure higher than the first pressure.

FIG. 7G shows a state in which the developing solutions 301Y, 301M, 301C, and 301K are supplied to the photosensitive belt 110 by the developing units 201Y, 201M, 201C, and 201K, thereby forming an electrostatic latent image. Here, the electrostatic latent image on the photosensitive belt 110 is formed by the electrostatic latent image by the LSU not shown in accordance with a conventional method. The developing rollers 205Y, 205M, 205C, and 205K of the developing units 201Y, 201M, 201C, and 201K are supplied with the developing solutions 301Y, 301M, 301C, and 301K supplied by the developer supply apparatuses 300Y, 300M, 300C, and 300K. Is applied to the photosensitive belt 110, and the squeeze rollers 204Y, 204M, 204C, and 204K squeeze the applied developer 301Y, 301M, 301C, and 301K to form a thin film, that is, a toner image. The toner image thus formed is transferred to a recording sheet (not shown) according to the conventional method.

7H to 7L illustrate the development rollers 205Y, 205M, 205C, and 205K of the developing units 201Y, 201M, 201C, and 201K, and the squeeze rollers 204Y, 204M, 204C, and 204K after the image formation is completed. It shows the drip line removal process that occurs when returning to the position and the development rollers 205Y, 205M, 205C, and 205K are separated from the photosensitive belt 110 during the process.

7H shows that when the non-image forming region including the joint portion of the photosensitive belt 110 approaches the developing roller 205Y of the first developing unit 201Y, the developing roller 205Y is lowered to the first position. As a result, the drip line 3011Y according to the aggregation of the developing solution 301Y generated when the developing roller 205Y is separated from the photosensitive belt 110 is formed. That is, as one of the characteristic elements of the image forming method of the present invention, the image forming method of the present invention separates the developing roller from the photosensitive belt when the non-image forming area approaches or contacts the developing roller, thereby forming a drip line in the non-image forming area. Will be.

7I shows that the photosensitive belt 110 proceeds further to approach the squeeze roller 204Y of the first developing unit 201Y, where the squeeze roller 204Y is lowered to the second position, that is, the photosensitive belt 110. Rotation in the reverse direction with respect to the traveling direction of the photosensitive belt 110 in a state in which the contact pressure for the) is reduced. Therefore, as shown in FIG. 7J, the drip line 3011Y formed in the non-image forming region 111 of the photosensitive belt 110 is removed by the squeeze roller 204Y. At this time, the developer from the drip line 3011Y transferred to the squeeze roller 204 is removed by the cleaning blade 207Y in contact with the lower portion of the squeeze roller 204Y.

7K illustrates that the non-imaging forming region 111 of the photosensitive belt 110 approaches the developing roller 204M of the second developing unit 201M, and then the developing roller 204M is lowered to the first position. Show status. At this time, first, the squeeze roller 204Y of the developing unit 201Y returns to the first position, that is, is separated from the photosensitive belt 110. Accordingly, the drip line 3011M is formed again in the non-image forming region 111 of the photosensitive belt 110, and the drip line is removed by the same procedure as described above. As the above-described operation of the rollers is repeated, the removal of the drip line for the photosensitive belt 110 is performed, and finally the state as shown in FIG. 7A is returned.

The embodiment of the image forming method of the present invention prevents damage to the photosensitive belt due to contact of the squeeze roller during the drip line by forming a drip line generated when the developing roller is separated from the photosensitive belt in the non-image forming region of the photosensitive belt. It is characteristic to doing.

Hereinafter, an embodiment according to the image forming apparatus of the wet printer of the present invention to which the image forming method according to the present invention is applied will be described.

Image Forming Device

Embodiment 1 of an image forming apparatus

8 shows the structure of the developing units 201Y, 201M, 201C, and 201K.

Referring to FIG. 8, the squeeze rollers 204Y, 204M, 204C, and 204K of the developing units 201Y, 201M, 201C, and 201K are supported by the mainframes 4000Y, 4000M, 4000C, and 4000K so as to be elastically moved up and down. Rotatable subframes 4010Y, 4010M, 4010C, and 4010K. On one side of the main frame (4000Y, 4000M, 4000C, 4000K) is a developing roller assembly (402Y, 402M, 402C, 402K) is coupled to the development roller (205Y, 205M, 205C, 205K). The supporters 4060Y, 4060M, 4060C, and 4060K supporting the subframe 4010 and the supporters 4060Y between the mainframes 4000Y, 4000M, 4000C, and 4000K and the subframes 4010Y, 4010M, 4010C, and 4010K. , 4060M, 4060C, 4060K) and compression springs 4070Y, 4070M, 4070C, 4070K that provide resilience between the subframes 4010Y, 4010M, 4010C, 4010K. The lower portions of the subframes 4010Y, 4010M, 4010C, and 4010K have missing portions 4011Y, 4011M, 4011C, and 4011K having a predetermined height. The supporters 4060Y, 4060M, 4060C, and 4060K are installed to move up and down relative to the mainframes 4000Y, 4000M, 4000C, and 4000K like the subframes 4010Y, 4010M, 4010C, and 4010K. Arms 4041Y, 4061M, provided with projections 4062Y, 4062M, 4062C, 4062K, which enter both missing portions 4011Y, 4011M, 4011C, 4011K of the subframes 4010Y, 4010M, 4010C, 4010K on both sides of the body. 4061C, 4061K) are formed. Accordingly, the subframes 4010Y, 4010M, 4010C, and 4010K are coupled to the supporters 4060Y, 4060M, 4060C, and 4060K by the arms 4041Y, 4061M, 4061C, and 4061K to allow relative movement of a predetermined distance. It is. At this time, since the compression springs 4070Y, 4070M, 4070C, and 4070K are located between the supporters 4060Y, 4060M, 4060C, 4060K and the subframes 4010Y, 4010M, 4010C, 4010K, the supporters 4060Y, 4060M, 4060C. , 4060K) and the subframes 4010Y, 4010M, 4010C, and 4010K are elastic in a direction away from each other, at this time by the protrusions 4042Y, 4062M, 4062C, 4062K of the arms 4041Y, 4061M, 4061C, 4061K. The maximum interval between the supporters 4060Y, 4060M, 4060C, 4060K and the subframes 4010Y, 4010M, 4010C, 4010K is limited to a predetermined range. On the other hand, the bottom of the supporter (4060Y, 4060M, 4060C, 4060K) is coupled to the cam stud (4050Y, 4050M, 4050C, 4050K) guided by the cam groove (4040Y, 4040M, 4040C, 4040K) of the cam slider 4030 have.

Therefore, the supporters 4060Y, 4060M, 4060C, and 4060K are moved up and down relative to the mainframe 4000 by the cam slider 4030 separately from the lifting operation of the mainframes 4000Y, 4000M, 4000C, and 4000K. do. Therefore, when the image is formed, the main frame (4000Y, 4000M, 4000C, 4000K) and the device for raising and lowering the horizontal movement of the cam slider 4030 in accordance with a series of operating sequence, the main frame ( Developing rollers (205Y, 205M, 205C, 205K) and squeeze rollers (204Y, 204M, 204C, 204K) coupled to 4000Y, 4000M, 4000C, 4000K) raise the developing rollers (205Y, 205M, 205C, 205K). Is positioned close to the photosensitive belt 110 while maintaining a predetermined distance, and is contacted with the photosensitive belt 110 at a predetermined pressure of the squeeze rollers 204Y, 204M, 204C, and 204K. In the above structure, the device for elevating the mainframe 4000 may be provided by the cam slider 4030, which is the same structure as elevating the subframes 4010Y, 4010M, 4010C, 4010K, That is, by providing a cam stud on one side of the main frame, the cam slider 4030 by providing a cam groove (4040Y, 4040M, 4040C, 4040K) corresponding to the cam stud (4050Y, 4050M, 4050C, 4050K), The cam slider 4030 enables the total lifting and lowering of the mainframes 4000Y, 4000M, 4000C, and 4000K, and the lifting and lowering motion of the subframe 4010 with respect to the mainframes 4000Y, 4000M, 4000C, and 4000K. do.

9 shows the cam grooves 4040Y, 4040M, 4040C, 4040K formed in the cam slider 4030 and the cam studs 4050Y, 4050M, 4050C, 4050K of each developing part 201Y, 201M, 201C, 201K guided by the cam grooves 4040Y, 4040M, 4040C, 4040K. Shows the relative position of. Here, the positions of the cam studs 4050Y, 4050M, 4050C, and 4050K are the squeeze rollers 204Y, 204M, 204C, and 204K of all the developing parts 201Y, 201M, 201C, and 201K, and the development rollers 205Y, 205M, 205C, 205K indicates a so-called home position (first position) separated from the photosensitive belt 110.

As shown in FIG. 9, the cam grooves 4040Y, 4040M, 4040C, and 4040K are all different in shape. This is because the cam studs 4050Y, 4050M, 4050C, 4050K guided to the cam grooves 4040Y, 4040M, 4040C, 4040K are sequentially squeezed rollers 204Y, 204M, 204C, 204K as in the image forming method of the present invention described above. It is intended to be descended.

In FIG. 9, when the cam slider 4030 gradually moves from right to left in the drawing, the cam studs 4050Y, 4050M, 4050C, and 4050K of each developing part 201Y, 201M, 201C, and 201K are moved from right to outside. The first position-> second position-> third position is raised. At this time, when the cam studs 4050Y, 4050M, 4050C, and 4050K are in the second position, the squeeze rollers 204Y, 204M, 204C, and 204K of the developing part 201Y, 201M, 201C, and 201K are exposed to the first pressure. When the belt 110 is in contact with the belt 110 and in the third position, the belt 110 is in contact with the photosensitive belt 110 at a second pressure higher than the first pressure.

10A to 10H show rising states of the squeeze rollers 204Y, 204M, 204C, and 204K of the respective developing parts 201Y, 201M, 201C, and 201K according to the sequential movement of the cam slider 4030. Reference is made to FIG. 7 described in Embodiment 2 of the chemical formation method of the present invention for better understanding in the following description of FIG. 10.

10A shows a state where the cam slider 4030 has progressed to the left by one step. At this time, only the cam stud 4050K of the developing part 201K on the left side rises from the first position to the second position, and as shown in FIG. 7B, the squeeze roller 204K also rises to the first pressure. Contact with the photosensitive belt 110.

10B shows a state where the cam slider 4030 proceeds to the second stage left. At this time, the cam stud 4050K of the leftmost developing part 201K remains in the second position, and then the cam stud 4050C of the developing part 201C is raised to the second position, as shown in Fig. 7C. Likewise, the squeeze roller 204C is raised to contact the photosensitive belt 110 at the first pressure. At this time, the developing roller 205K of the first developing unit 201K is raised by a separate device to approach the photosensitive belt 110.

10C shows a state where the cam slider 4030 has progressed to the left by three stages. From the left, the cam studs 40504K and 4050C of the two developing parts 201K and 201C remain in the second position, and then the cam stud 4050M of the third developing part 201M rises to the second position. As shown in FIG. 7D, the squeeze roller 204M of the third developing unit 201M contacts the photosensitive belt 110 at a first pressure.

10D shows a state where the cam slider 4030 proceeds to the left by four steps. From the left, the cam studs 40504K, 4050C, and 4050M of the three developing parts 201K, 201C, and 201M remain in the second position, followed by the cam studs 4050Y of the fourth developing part 201Y. And as shown in FIG. 7F, the squeeze roller 204Y of the fourth developing portion 201Y is brought into contact with the photosensitive belt 110 at the first pressure. When this stage is reached, the cam studs 4050Y, 4050M, 4050C, and 4050K of all the developing parts 201Y, 201M, 201C, and 201K are positioned in the second position so that all the squeeze rollers 204Y, 204M, 204C, and 204K are the first. The developing rollers 205Y, 205M, 205C, and 205K, which are in contact with the photosensitive belt 110 by pressure, and are driven separately, are raised to the third position to approach the photosensitive belt 110. FIG.

10E to 10G below show the order in which the cam studs 4050Y, 4050M, 4050C, and 4050K ascend in the second position to the third position, as shown in the above-described movement to the second position. The squeeze roller moving from the stud to the third position and raised to the third position is contacted at a second pressure higher than the first pressure. 10E to 10H will be briefly described.

FIG. 10E shows that the cam slide 4030 is moved to the left in the fifth step, and the first cam stud 4050K is lifted to the third position from the left.

FIG. 10F shows a state where the cam slide 4030 is moved to the left in the sixth step, and the second cam stud 4050C is lifted to the third position from the left.

10G shows that the cam slide 4030 has moved to the left in the seventh step, and the third cam stud 4050C from the left is raised to the third position.

10H shows that the cam slide 4030 is moved to the left in the seventh step, and the fourth cam stud 4050C from the left is raised to the third position. At this stage, the developing rollers 205Y, 205M, 205C, 205K and the squeeze rollers 204Y, 204M, 204C, 204K of all the developing parts 201Y, 201M, 201C, and 201K are completed, and then the conventional Image forming is performed through the process, and after image forming is completed, the development rollers 205Y, 205M, 205C, and 205K and the squeeze rollers 204Y, 204M, 204C, and 204K are gradually turned from right to left in the reverse order of the above-described order. Descend in the order of direction.

In the descending step, the drip line removal process as described above is performed in the step where the squeeze rollers 204Y, 204M, 204C, and 204K are in the second position. According to the above method, the developing rollers are lowered in that order in synchronization with the progress of the photosensitive belt so that a drip line generated when the developing roller is separated from the photosensitive belt 110 is formed in the non-image forming region of the photosensitive belt. The drip line is formed in the non-image area of the photosensitive belt, and the drip line is removed while rotating the squeeze roller contacted with the photosensitive belt at the first pressure. To this end, while continuously detecting the driving position of the photosensitive belt provided in a conventional wet printer, when the non-image forming region of the photosensitive belt approaches the upper part of the developing roller of each developing part, the developing roller at the bottom thereof is lowered and the drip line is lowered. Is formed in the non-imaging region, and the squeeze roller of the developing part is rotated in reverse while contacting the photosensitive belt with the first pressure to remove the drip line. Such drip lines are removed at regular time intervals for each developing unit.

The image forming apparatus of the present invention described above is driven to drive the squeeze rollers 204Y, 204M, 204C, and 204K of the developing units 201Y, 201M, 201C, and 201K step by step, so as to drive the cam slider. The required power is reduced. In addition, by synchronizing the stepwise movement of the cam slider to the driving of the photosensitive belt, the drip line inevitably generated at the time of returning to the developing roller is formed in the non-image forming region of the photosensitive belt without fear of damage, thereby causing an image of the photosensitive belt. The forming area is not damaged. Embodiment 1 of the image forming apparatus described above allows all the squeeze rollers to be operated by one driving source, while the development rollers are operated individually by a separate driving source or by one other driving source such as squeeze rollers. Was explained. The second embodiment of the image forming apparatus described below has a structure in which the development rollers 205Y, 205M, 205C, and 205K and the squeeze rollers 204Y, 204M, 204C, and 204K are driven by one driving source.

Embodiment 2 of an image forming apparatus

11 shows the structure of the developing units 201Y, 201M, 201C, and 201K according to the present embodiment.

Referring to FIG. 11, the squeeze rollers 204Y, 204M, 204C, and 204K of the developing units 201Y, 201M, 201C, and 201K are supported by the mainframes 4000Y, 4000M, 4000C, and 4000K to be elastically lowered. Rotatable subframes 4010Y, 4010M, 4010C, and 4010K. On one side of the main frame (4000Y, 4000M, 4000C, 4000K) is a developing roller assembly (402Y, 402M, 402C, 402K) is coupled to the development roller (205Y, 205M, 205C, 205K). The supporters 4060Y, 4060M, 4060C, and 4060K supporting the subframe 4010 and the supporters 4060Y between the mainframes 4000Y, 4000M, 4000C, and 4000K and the subframes 4010Y, 4010M, 4010C, and 4010K. , 4060M, 4060C, 4060K) and compression springs 4070Y, 4070M, 4070C, 4070K that provide resilience between the subframes 4010Y, 4010M, 4010C, 4010K. The lower portions of the subframes 4010Y, 4010M, 4010C, and 4010K have missing portions 4011Y, 4011M, 4011C, and 4011K having a predetermined height. The supporters 4060Y, 4060M, 4060C, and 4060K are installed to move up and down relative to the mainframes 4000Y, 4000M, 4000C, and 4000K like the subframes 4010Y, 4010M, 4010C, and 4010K. Arms 4041Y, 4061M, provided with projections 4062Y, 4062M, 4062C, 4062K, which enter both missing portions 4011Y, 4011M, 4011C, 4011K of the subframes 4010Y, 4010M, 4010C, 4010K on both sides of the body. 4061C, 4061K) are formed. Accordingly, the subframes 4010Y, 4010M, 4010C, and 4010K are coupled to the supporters 4060Y, 4060M, 4060C, and 4060K by the arms 4041Y, 4061M, 4061C, and 4061K to allow relative movement of a predetermined distance. It is. At this time, since the compression springs 4070Y, 4070M, 4070C, and 4070K are located between the supporters 4060Y, 4060M, 4060C, 4060K and the subframes 4010Y, 4010M, 4010C, 4010K, the supporters 4060Y, 4060M, 4060C. , 4060K) and the subframes 4010Y, 4010M, 4010C, and 4010K are elastic in a direction away from each other, at this time by the protrusions 4042Y, 4062M, 4062C, 4062K of the arms 4041Y, 4061M, 4061C, 4061K. The maximum interval between the supporters 4060Y, 4060M, 4060C, 4060K and the subframes 4010Y, 4010M, 4010C, 4010K is limited to a predetermined range. On the other hand, the first cam studs 4050Y, 4050M, 4050C, 4050K guided by the first cam grooves 4040Y, 4040M, 4040C, 4040K of the cam slider 4030 at the lower part of the supporters 4060Y, 4060M, 4060C, 4060K. ) Is combined. The second cam studs 4090Y, 4090M, 4090C, and 4090K are guided by the second cam grooves 4080Y, 4080M, 4080C, and 4080K of the cam slider 4030 in the lower part of the main frames 4000Y, 4000M, 4000C, and 4000K. ) Is formed.

Accordingly, the supporters 4060Y, 4060M, 4060C, 4060K and the mainframes 4000Y, 4000M, 4000C, and 4000K are each of the first cam grooves 4040Y, 4040M, 4040C, 4040K and the second cam groove of the cam slider 4030. (4080Y, 4080M, 4080C, 4080K), respectively. Accordingly, when the camshader 4030 is horizontally driven during image formation, the driving device moves in a series of steps in synchronism with the transfer of the photosensitive belt, thereby to the mainframes 4000Y, 4000M, 4000C, and 4000K. The combined developing rollers 205Y, 205M, 205C, and 205K and the squeeze rollers 204Y, 204M, 204C, and 204K are raised, respectively, so that the developing rollers 205Y, 205M, 205C, and 205K are connected to the photosensitive belt 110. It is placed close to each other at a predetermined interval and contacts the photosensitive belt 110 at a predetermined pressure of the squeeze rollers 204Y, 204M, 204C, and 204K.

FIG. 12 shows the first cam grooves 4040Y, 4040M, 4040C, and 4040K formed by the cam slider 4030 and the first cam studs 4050Y, 4050M, of the respective developing parts 201Y, 201M, 201C, and 201K. 4050C, 4050K) and the second cam grooves 4080Y, 4080M, 4080C, 4080K and the relative cam studs 4090Y, 4090M, 4090C, 4090K are shown. Here, the positions of the first cam studs 4050Y, 4050M, 4050C, and 4050K and the second cam studs 4090Y, 4090M, 4090C, and 4090K are located at the squeeze rollers 204Y, of all the developing units 201Y, 201M, 201C, and 201K. 204M, 204C, and 204K and the development rollers 205Y, 205M, 205C, and 205K show a so-called home position (first position) in which the photosensitive belt 110 is separated.

The operation of the embodiment according to the image forming apparatus of the present invention having the above structure is the same as that of the first embodiment described above.

FIG. 13 is a time chart showing the first and second cam groove curves for the operation of the second embodiment of the image forming apparatus of the present invention as described above.

In FIG. 13, Y represents yellow developing unit 201Y, M represents magenta developing unit 201M, C represents cyan developing unit 201C, and K represents black developing unit 201K.

As shown in Fig. 13, the developing roller, the squeeze roller, and the (cleaning) blade of each developing unit operate sequentially. In the figure, the left to right direction represents the ascending process, and the reverse to the descending process. As shown, the squeeze roller of the developing parts is guided by a cam groove having three positions, and the developing roller and the blade are guided by two cam grooves. In particular, the developing roller of each developing part rises from the first position to the second position when the cam stud guiding the squeeze roller reaches the third position, and the blade is raised when the squeeze roller is in the second position and the rest thereof. The position remains lowered. That is, the blade is raised only in contact with the squeeze roller in the second position, that is, when the squeeze roller is in the drip line removal mode. Therefore, while the structure for raising and lowering the blade is not described above, another cam stud for the operation of the blade is formed in the blade through FIG. 13, and the cam groove to which the cam stud is guided is formed in the cam slider. Can be formed.

Meanwhile, the developing units 201Y, 201M, 201C, and 201K as described above have compression springs 4070Y, 4070M, between the subframes 4010Y, 4010M, 4010C, 4010K, and the supporters 4060Y, 4060M, 4060C, 4060K. 4070C, 4070K) are located, and this structure is a structure in which the pressure of the squeeze roller against the photosensitive belt is generated when the compression spring is inflated and then compressed. Contrast with the structure of For example, when the cam slider 4030 moves stepwise in the direction of raising the squeeze rollers 204Y, 204M, 204C, 204K and the development rollers 205Y, 205M, 205C, 205K, the first cam groove 4040Y, 4040M. The supporters 4060Y, 4060M, 4060C, and 4060K are moved upward by the first cam studs 4050Y, 4050M, 4050C, and 4050K guided to the 4040C and 4040K, and the compression springs 4070Y, 4070M, 4070C, Lifting force is generated by the elasticity of the compression springs 4070Y, 4070M, 4070C, and 4070K in the subframes 4010Y, 4010M, 4010C, and 4010K supported by 4070K, and thus the subframes 4010Y, 4010M, and 4010C. , The squeeze roller 204 supported by 4010K is in contact with the photosensitive belt 110 at a constant pressure. At this time, the spring 4070 is maintained in a compressed amount.

According to the above structure, the contact pressure of the squeeze roller is provided by a spring compressed by a certain amount. That is, the spring is inflated a certain amount within the maximum distance allowed between the supporter and the subframe when the idle time, that is, when the supporter is not raised, and when the imager is raised, that is, when the supporter is raised. While compressed, it provides the contact pressure of the squeeze roller.

Therefore, according to the image forming apparatus of the present invention, since the spring is sufficiently inflated during the normal idle time, plastic deformation does not occur through this period, and this period is compressed only for a short time during the image forming period. Plastic deformation through not much occur. This feature is contrasted with the case in the conventional image forming apparatus. That is, in the conventional image forming apparatus, the spring is compressed during the idle time, and the contact pressure is generated while the spring is inflated to form the image. Therefore, the plastic deformation during the compressed idle time occurs greatly, and in particular, the spring is compressed. Since the contact pressure is generated while changing from the expanded state to the expanded state, a spring having a strength considering the amount of expansion from the compressed state to the expanded state, that is, a spring having a high elasticity, should be applied.

As described above, according to the image forming apparatus of the present invention, it is possible to effectively control the contact pressure of the squeeze roller to the photosensitive belt, in particular to prevent plastic deformation due to fatigue accumulation of the spring providing the contact pressure, It is possible to prevent deterioration of the function of the squeegee roller due to a change in contact pressure, in particular a decrease. In addition, by multi-stage the contact pressure of the squeeze roller, it is possible to reduce the load of the power source that operates the squeeze roller, and in particular, by appropriately adjusting the contact pressure of the squeeze roller during the image formation process and the removal of the drip line, it effectively squeezes the photosensitive belt. The drip line can be removed as well as the gong. In addition, since the output of the power source for operating the squeeze roller and the development roller can be lowered, the cost of the component can be reduced by the power source having a low output, and the manufacturing cost can be reduced since a material having a lower mechanical strength can be used as compared with the conventional art. Further, by forming the drip line in the non-image forming region of the photosensitive belt, it is possible to prevent damage to the image forming region of the photosensitive belt by the squeeze roller which rubs against the photosensitive belt at high pressure.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only in the appended claims.

Claims (23)

A developing roller is applied to a photosensitive belt having a non-image forming area by moving a developer of a predetermined color supplied by a developer supplying device of a wet printer, and a squeeze for removing excess developer from the developer supplied to the photosensitive belt. In the image forming method using a wet printer having a plurality of unit development unit having a roller, An initial positioning step of placing the developing rollers and the squeeze rollers of all the unit developing parts at a first position spaced apart from the photosensitive belt by a predetermined distance; The squeeze rollers of the unit developing parts arranged in the traveling direction of the photosensitive belt are sequentially raised to the second position, and the squeeze rollers are sequentially raised in the reverse order of the traveling direction of the photosensitive belt, so that each squeeze roller is made with respect to the photosensitive belt. A squeeze roller raising step of contacting at one pressure; A developing roller raising step of raising the developing rollers to a third position so that the developing rollers of the unit developing units are positioned at a predetermined interval on the photosensitive belt, and sequentially raising the developing rollers in the reverse order of the traveling direction of the photosensitive belt. ; An image for developing an electrostatic latent image formed on the photosensitive belt as a toner image by supplying a developer solution between the developing roller and the photosensitive belt in a state where at least one of the squeeze rollers and the developing roller is located at the second position and the third position, respectively. Forming step; A developing roller returning step of returning the developing rollers of the unit developing units in the third position to the first position, and sequentially lowering the developing rollers in the order of traveling direction of the photosensitive belt; And returning the squeeze rollers of the unit developing units in the second position to the first position, and returning the squeeze rollers to sequentially lower the developing rollers in the order of traveling direction of the photosensitive belt. And each squeeze roller and the developing roller of the unit developing unit are moved up and down with a parallax. The method of claim 1, wherein the developing roller raising step further includes a boosting step of causing the squeeze roller to be contacted at a second pressure higher than the contact pressure of each squeeze roller to the photosensitive belt in the rising step of the squeeze roller. An image forming method. The image forming method according to claim 1, further comprising reducing the contact pressure of the squeeze roller contacted to the photosensitive belt with a second pressure to the first pressure during the developing roller returning step. 2. The image forming method according to claim 1, wherein in the squeeze roller raising step, the squeeze roller at the second position in contact with the photosensitive belt is rotated in the direction in which the photosensitive belt proceeds. The image forming method according to claim 1 or 4, wherein, in the image forming step, the developing roller and the squeeze rollers are rotated in the advancing direction of the photosensitive belt. A developing roller is applied to a photosensitive belt having a non-image forming area by moving a developer of a predetermined color supplied by a developer supplying device of a wet printer, and a squeeze roller to remove excess developer from the developer supplied to the photosensitive belt. In the image forming method using a wet printer having a plurality of unit developing unit having a; An initial positioning step of placing the developing rollers and the squeeze rollers of all the unit developing parts at a first position spaced apart from the photosensitive belt by a predetermined distance; The squeeze rollers of the unit developing parts arranged in the traveling direction of the photosensitive belt are sequentially raised to the second position, and the squeeze rollers are sequentially raised in the reverse order of the traveling direction of the photosensitive belt, so that each squeeze roller is removed from the photosensitive belt. A squeeze roller raising step of contacting at one pressure; A developing roller raising step of raising the developing rollers to a third position so that the developing rollers of the unit developing units are positioned at a predetermined interval on the photosensitive belt, and sequentially raising the developing rollers in the reverse order of the traveling direction of the photosensitive belt. ; The electrostatic latent image formed on the photosensitive belt was developed as a toner image by supplying a developer solution between the developing roller and the photosensitive belt with the squeeze roller and the developing roller of at least one of the unit developing parts respectively positioned at the second position and the third position. An image forming step; The developing rollers of the unit developing units in the third position are returned to the first position, and the developing rollers are sequentially lowered in the order of the traveling direction of the photosensitive belt. When the non-image forming region of the belt is positioned, the lens is returned to the first position so that a drip line formed in the photosensitive belt is generated in the non-image forming region of the photosensitive belt as the respective developing rollers of the unit developing parts fall. Return step; A drip line removing step of removing a drip line formed when the developing roller is separated from the photo belt while rotating the squeeze roller contacted with the photosensitive belt at a predetermined pressure; An squeeze roller returning step of returning the squeeze rollers of the unit developing units at the second position to the first position and sequentially lowering the developing rollers in the order of the traveling direction of the photosensitive belt; Way. 7. The image forming method according to claim 6, wherein each of the squeeze rollers and the developing rollers of each unit developing part is moved up and down with a parallax. The method according to claim 6, wherein the developing roller raising step further comprises a boosting step for causing the squeeze roller to be contacted at a second pressure higher than the contact pressure of each squeeze roller to the photosensitive belt in the rising step of the squeeze roller. An image forming method. 7. The image forming method according to claim 6, further comprising the step of depressurizing the contact pressure of the squeeze roller contacted to the photosensitive belt with the second pressure to the first pressure during the developing roller returning step. The image forming method according to claim 6, wherein, in the step of raising the squeeze roller, the squeeze roller of the second position in contact with the photosensitive belt is rotated in a direction in which the photosensitive belt is advanced. The image forming method according to claim 6 or 10, wherein in the image forming step, the developing roller and the squeeze rollers are rotated in the advancing direction of the photosensitive belt. Developing rollers which apply to a photosensitive belt having a non-image forming area by moving a developer of a predetermined color supplied by a developer supplying device of a wet printer in one direction; A squeeze roller for removing excess developer from the developer supplied with the photosensitive belt; A main frame supporting the developing roller; A subframe in which the squeeze roller is elastically supported vertically and supported by the main frame in a descending manner; A plurality of unit developing units provided; A main frame elevating device for elevating the main frames of the unit developing units; A subframe elevating device for elevating the subframe with respect to the mainframe; An image forming apparatus of a wet printer provided, The subframe elevating device may include: raising and lowering the subframe step by step by interfering with the subframe to a second first position, an intermediate second position, and an upper third position, and raising the subframe. It is configured to sequentially raise the sub-frames of the unit developing units in the reverse order of the transport direction of, and to lower the sub-frames of the unit developing units in the transport direction of the photosensitive belt when the sub-frame is lowered, The main frame elevating device includes: interfering the main frame to raise and lower the first position and the second position higher than the first position, and the unit in the reverse order of the feeding direction of the photosensitive belt when the main frame is raised. It is configured to sequentially raise the mainframes of the developing portion, and to sequentially lower the subframes of the unit developing portion in the conveying direction of the photosensitive belt when the mainframe is lowered, And each of the squeeze rollers and the developing rollers of the unit developing unit are configured to move up and down at a time difference. The method of claim 12, wherein the squeeze roller is in contact with the photosensitive belt in the second position and the third position, the contact pressure of the squeeze roller with respect to the photosensitive belt in the third position is higher than the contact pressure in the second position An image forming apparatus of a wet printer, characterized in that configured to. The apparatus of claim 12, wherein the squeeze roller is rotated in a direction opposite to the direction in which the photosensitive belt travels when the subframe is lowered from the third position to the second position. The apparatus of claim 12, wherein the developing roller and the squeeze roller are rotated in the advancing direction of the photosensitive belt when the subframe is in the third position. The method according to any one of claims 12 to 15, wherein the main frame elevating device and the subframe elevating device are provided with a cam stud in each of the main frame and the subframes of the unit developing units, The cam studs are guided respectively, and are provided by providing a plurality of cam grooves for determining a first position and a second position of the main frame, and a first position, a second position, and a third position of the subframe. An image forming apparatus of a wet printer. The method according to any one of claims 12 to 15, wherein the unit developing unit comprises: a subframe in which the squeeze roller is rotatably mounted; A main frame in which the subframe is supported to move up and down a predetermined distance; A compression spring supporting the subframe from below to provide an elastic lifting force to the subframe; A supporter for supporting a lower portion of the spring; And a cam stud provided at the supporter with respect to the main frame, the cam stud being guided to the cam groove of the cam slider. 18. The apparatus of claim 17, wherein a cam stud guided to a cam groove provided in the cam slider is provided in the main frame. 19. The image forming apparatus of claim 18, wherein the cam groove provided in the cam slider to guide the cam stud of the supporter is formed to have the position of the supporter having three levels of different heights from each other. The apparatus of claim 16, wherein the unit developing unit comprises: a subframe to which the squeeze roller is rotatably mounted; A main frame in which the subframe is supported to move up and down a predetermined distance; A compression spring supporting the subframe from below to provide an elastic lifting force to the subframe; A supporter for supporting a lower portion of the spring; And a cam stud provided at the supporter with respect to the main frame, the cam stud being guided to the cam groove of the cam slider. 21. The image forming apparatus of claim 20, wherein a cam stud guided to a cam groove provided in the cam slider is provided in the main frame. 22. The image of a wet printer according to claim 20 or 21, wherein the cam groove provided in the cam slider so as to guide the cam stud of the supporter is formed so that the supporters have three levels of positions different from each other in height. Forming device. 19. The image forming apparatus of claim 18, wherein the cam groove provided in the cam slider to guide the cam stud of the supporter is formed to have the position of the supporter having three levels of different heights from each other.