JPH11188855A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of stabilizing the image formed on an image forming medium by a recording liquid and capable of forming an image of good quality. SOLUTION: An ink jet printer 1 has a feed roller 4 for feeding paper P through a predetermined feed passage. A printing head 20 emitting ink droplets toward the fed paper P corresponding to an image signal and a post-processing device 22 for stabilizing the image formed on the paper P through the printing head 20 are provided on the feed passage of the paper P. In the post-processing apparatus 22, colorless transparent powder particles having a porous structure are supplied to the paper P on which the image is held by ink and the image (ink) on the paper P is prevented from adhering to other member undesirably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus which discharges a recording liquid toward an image forming medium and forms an image on the image forming medium using the recording liquid.

[0002]

2. Description of the Related Art Conventionally, an ink jet printer is known as an image forming apparatus for forming an image on a medium on which an image is to be formed by discharging ink droplets in accordance with an image signal. Ink jet printers include a bubble jet method that heats ink to generate bubbles and ejects ink droplets, a piezo method that drives piezoelectric elements to eject ink droplets, and ejects ink droplets by forming an electric field in the ink. There is an electrostatic method to be performed.

In an ink jet printer of this type, since ink droplets land on a medium on which an image is to be formed, if plain paper or the like having a relatively coarse texture is used as the medium on which the image is to be formed, bleeding of the image occurs due to diffusion of the ink. There are cases. For this reason, glossy paper in which a resin layer is applied to the surface of a medium such as plain paper is generally used as an image forming medium.

[0004]

However, when a plurality of types of inks having different densities are used to obtain high image quality, or when a black solid image is formed by superimposing inks of respective colors,
The amount of ink landed on the glossy paper increases, and the resin layer of the glossy paper swells with a large amount of ink. in this case,
It takes a relatively long time to dry the ink, and if the resin layer overlaps and comes into contact with other media before the ink is completely dried, the ink may cause the media to adhere to each other. I was In addition, when the medium thus adhered is peeled off, the resin layer of the glossy paper is peeled off from the base material.

An object of the present invention is to provide an image forming apparatus capable of stabilizing an image by a recording liquid formed on an image forming medium and forming a high quality image. Is to provide.

[0006]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention discharges a recording liquid toward an image forming medium and records the recording liquid on the image forming medium. An image forming means for forming an image with the liquid, and supplying powder to the surface of the image forming medium on which the image with the recording liquid has been formed by the image forming means to prevent the image from touching another object Powder supply means.

Further, according to the image forming apparatus of the present invention, the powder is colorless and transparent. According to the image forming apparatus of the present invention, the powder has a porous structure.

According to a fourth aspect of the present invention, there is provided an image forming apparatus, wherein a conveying means for conveying an image forming medium, and a recording liquid is discharged toward the image forming medium conveyed by the conveying means. An image forming means for forming an image with a recording liquid on an image forming medium, a storage part provided downstream of the image forming means in the transport direction, and containing a powder having a colorless and transparent porous structure; A supply member for supplying the powder contained in the medium to the surface of the image forming medium on which the image is formed by the recording liquid by the image forming means, and an adjusting mechanism for adjusting the supply amount of the powder by the supply member. And
A powder supply unit configured to supply the powder whose supply amount has been adjusted to the surface so as to prevent an image formed on the surface from touching another object.

Further, according to the image forming apparatus of the present invention, the supply member is brought into contact with the surface of the image forming medium conveyed by the conveying means on which the image is formed, and is provided on the peripheral surface thereof. An application roller is provided for holding the powder in the storage section and rotating the powder to apply the held powder to the surface.

Further, according to the image forming apparatus of the present invention, the powder supply means is selectively operated only when a mode for supplying powder to the image forming medium is selected. According to another aspect of the present invention, there is provided an image forming apparatus, comprising: a conveying unit that conveys an image forming medium; and a recording liquid that is ejected toward the image forming medium conveyed by the conveying unit. An image forming unit that forms an image with a recording liquid on a forming medium; and an image forming unit that is provided downstream of the image forming unit in the transport direction and on which an image with the recording liquid is formed by the image forming unit. Drying means for drying the image with the recording liquid by applying heat.

Further, according to the image forming apparatus of the present invention, the drying means is selectively operated only when a mode for drying an image using a recording liquid is selected.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 schematically shows a main part of an ink jet printer as an image forming apparatus according to the present invention. The inkjet printer 1 (hereinafter simply referred to as the printer 1) includes a housing 2 forming an outer shell of the printer 1.
have.

A transport roller 4 for transporting the paper P is disposed at a substantially central position of the housing 2 so as to be rotatable in the direction of the arrow in the figure. The printer 1 is located on the right side of the housing 2 in the drawing.
And a paper discharge tray 8 for receiving the paper P discharged from the printer 1. The paper P is glossy paper having a resin layer formed on the surface of plain paper.

A pair of paper sheets P set on the paper feed tray 6 are pinched and taken into the housing 2 and transported toward the transport rollers 4 on a transport path from the paper feed tray 6 to the transport rollers 4. A paper feed roller 12 is provided. A transport guide 14 that guides the lower surface of the sheet P transported via the transport roller 4 is provided on a transport path from the transport roller 4 to the paper discharge tray 8, and a transport guide 14.
The paper P guided by the
A pair of paper discharge rollers 16 for discharging the paper onto the paper discharge tray 8 are provided. Further, a plurality of guide rollers 18 that guide the sheet P conveyed via the conveyance roller 4 between the conveyance rollers 4 are rolled on the circumference of the conveyance roller 4.

The paper P set on the paper feed tray 6 is taken in by the paper feed roller 12 and conveyed along the conveyance roller 4. At this time, the paper P is transported between the plurality of guide rollers 18 and the transport roller 4. The sheet P transported via the transport rollers 4 is guided by a transport guide 14 and is discharged onto a discharge tray 8 by discharge rollers 16.

On the left side of the transport roller 4 in the figure, there is provided an ink jet type print head 20 arranged at a predetermined distance from the peripheral surface of the transport roller 4. Print head 2
0 discharges ink droplets corresponding to the image signal toward the paper P conveyed via the conveyance roller 4 to form an image on the paper P. The image signal is input to the print head 20 via an external device such as a personal computer.

Above the transport guide 14, an image is formed via the print head 20, and the post-processing device is opposed to the surface (front surface) on which the image of the paper P transported on the transport guide 14 is formed. 22 (detailed later) are provided. The post-processing device 22 processes the image on the paper P via the print head 20 so that the image formed by the ink liquid formed on the paper P is stabilized.

Thus, printing conditions such as the type of paper P set in the printer 1, the degree of print quality, the image processing method, and the type of ink (recording liquid) are set via an external device such as a personal computer. When the print execution command is input, the conveyance of the paper P is started as described above, and the paper P is sent to the print head 20. The print head 20 ejects ink droplets corresponding to the image signal toward the surface of the paper P, and forms an image on the surface of the paper P by conveying the paper P and scanning the print head 20. Then, the sheet P on which the image is formed
Is sent to the post-processing device 22, where it is subjected to the processing described later and discharged.

At this time, when glossy paper having a resin layer on the surface is set in the printer 1, when the use of glossy paper is set as a printing condition, a mode for operating the post-processing device 22 is automatically set. Then, predetermined processing is performed on the glossy paper via the post-processing device 22. This setting can be arbitrarily released.

FIG. 2 shows a post-processing apparatus according to a first embodiment of the present invention, which supplies powder particles (hereinafter simply referred to as powder) to an image formed on the surface of a sheet P. 1 schematically shows a coating device 30 acting as a powder supply means for stabilizing an image.

The coating apparatus 30 has a storage chamber 31 for storing a colorless and transparent powder having a porous structure. In the present embodiment, polymethyl methacrylate, nylon 6, nylon 11, nylon 1
2. Porous nylon, polyethylene, polystyrene,
Polymer particles such as cross-linked polystyrene, polyester, styrene acrylic resin, ethylene-acrylic acid, cross-linked acrylic resin, silicone resin, fluorine resin, epoxy resin, phenol resin, calcium carbonate, magnesium carbonate, magnesium silicate, barium sulfate, and silica And inorganic pigment particles such as talc, mica, and alumina. In addition, particles having a relatively small dynamic friction coefficient (0.5 or less) are used as powder due to a problem in transportation.

An application roller 32 for supplying powder onto the surface of the sheet P conveyed via the conveyance guide 14 is provided below the accommodation chamber 31. Above the application roller 32 and in the accommodation chamber 31, there is provided a transport roller 33 that rotates and scatters the powder contained in the accommodation chamber 31 onto the peripheral surface of the application roller 32. I have. Between the transport roller 33 and the application roller 32, a partition wall 39 having a passage for powder is provided.
A shutter 34 slidably provided between a closed position for restricting the powder from falling and an open position for opening the passage.
Is provided.

On the peripheral surface of the application roller 32, a blade for adjusting the amount of powder scattered on the peripheral surface of the application roller 32 to form a thin film of the powder on the peripheral surface. 35 are provided. Further, on the peripheral surface of the application roller 32, a cleaning roller 36 that removes powder remaining on the peripheral surface of the application roller 32 without being supplied onto the surface of the paper P by the application roller 32 is provided. .

When a print execution command is input from an external device (not shown) or the like and the conveyance of the paper P is started,
The shutter 34 is slid to the open position and the transport roller 3
The rotation of No. 3 is started. As a result, the powder stored in the storage chamber 31 is transported by the rotation of the transport roller 33 and is scattered on the peripheral surface of the application roller 32. The amount of the powder dropped on the peripheral surface of the application roller 32 is adjusted by passing through the gap between the application roller 32 blade 35 and the application roller 32, and the powder is conveyed on the conveyance guide 14. It is supplied on paper P. At this time,
The application roller 32 is in rolling contact with the sheet P conveyed along the conveyance guide 14, and the powder held on the peripheral surface of the application roller 32 is supplied onto the surface of the sheet P on which an image is formed. After the powder is supplied onto the paper P, the powder remaining on the peripheral surface of the application roller 32 is removed by the cleaning roller 3.
6 is cleaned.

If the mode in which the coating device 30 is not operated is selected at the time of setting the printing conditions,
While the shutter 34 is slid to the closing position, the transport roller 33 is also stopped, and the application roller 32 functions as a transport roller for transporting the paper P.

As described above, according to the present embodiment, the colorless and transparent powder having the porous structure is supplied onto the surface of the paper P on which the image is formed by the ink liquid. Image can be stabilized. That is, by bringing the powder having the porous structure into contact with the ink, the solvent of the ink can be satisfactorily adsorbed on the enlarged surface of the powder (the porous structure increases the surface area of the powder). In addition, the drying of the ink can be promoted. Further, by supplying the powder onto the surface of the sheet P on which the image is formed, it is possible to suppress the sheet P on which the image is formed from directly touching another object. Further, by making the powder colorless and transparent, the recognition of the image formed on the paper P is not hindered.

Therefore, according to the present embodiment, it is possible to prevent the problem that the sheet P is adhered to another object due to the drying of the ink. For example, when the paper P on which an image is formed is placed in a clear file formed of transparent vinyl or the like, the image (ink) formed on the paper P adheres to the file, or the resin layer of the paper P It can be prevented from peeling off.

FIG. 3 schematically shows, as a post-processing device according to a second embodiment of the present invention, a drying device 40 acting as a drying means for drying an image formed on the surface of a sheet P. It is.

The drying device 40 includes three rollers 41, 42, 43 that are driven to rotate by a motor (not shown), and a belt 4 that is wound around and stretched around these three rollers.
Four. The belt 44 is formed by applying a Teflon coat or the like to the surface of a metal belt such as SUS. The roller 41 at the lowermost position of the three rollers, that is, at the position facing the sheet P to be conveyed,
The belt 44 is positioned so that the linear pressure of the belt 44 with respect to the pressure is 2 kg / cm or less.

Belt 4 stretched between rollers 41 and 42
A sensor 45 for detecting the surface temperature of the belt 44 is disposed in contact with the surface of the belt 4. Also, the sensor 4
5, the downstream side in the running direction of the belt 44, that is, the rollers 42,
The surface of the belt 44 stretched between 43
Is provided in contact with the heater 46 for heating the heater. The heating temperature of the belt 44 by the heater 46 is set to such a degree that the resin layer on the surface of the paper P is not melted (12
0 ° C or less).

When the printing operation is started, the rollers 41, 42 and 43 are rotated, and the running of the belt 44 is started. At the same time, the heater 46 is turned on and the belt 4
4 is started, and the surface temperature of the belt 44 is monitored by the sensor 45. Then, on / off control of the heater 46 is performed so that the surface temperature of the belt 44 becomes constant. In this state, the paper P is transported and
, The image formed on the surface of the paper P is heated and dried.

When the mode in which the drying device 40 is not operated is selected, the belt 44 functions only as a transport belt for transporting the paper P without being heated by the heater 46.

As described above, according to this embodiment, the image formed by the ink formed on the surface of the paper P can be forcibly dried, and the same effects as those of the first embodiment can be obtained. Can play.

Next, the image stability when an image is formed on a commercially available glossy paper using the printer 1 will be described based on the following experimental results.

In the experiments, the first embodiment uses the coating apparatus 30 as a post-processing apparatus, the second embodiment uses the drying apparatus 40 as a post-processing apparatus, and the comparative example uses no post-processing apparatus. And In the first embodiment,
Calcium carbonate was used as powder to be supplied to glossy paper.
In the second embodiment, the surface temperature of the belt 44 is set to 100 ° C.
, And the linear pressure of the belt 44 was set to 0.05 kg / cm.

Then, in each case, 1 cm
A band-shaped color gradation pattern chart having a width is output on A4 size glossy paper, and the glossy paper on which the pattern image is formed is
Immediately after the image formation, 1 minute, 5 minutes, and 10 minutes later, a 1 kg weight of A4 size was placed in a commercially available vinyl clear file, left for 30 minutes, and the state of the pattern image was examined. The black (B) image was output by superimposing the yellow (Y), magenta (M), and cyan (C) images. The results are shown in the table of FIG.

According to this, in the comparative example in which the post-processing device was not operated, the gloss paper immediately after the pattern image was formed was examined. As a result, the ink was cleared at the relatively high-density black image portion where the inks of the respective colors were superimposed. When the glossy paper was peeled off from the clear file, the resin layer of the glossy paper was peeled off together with the ink when the glossy paper was peeled off (clear; x). Similar results were obtained for glossy paper 1 minute and 5 minutes after the image was formed. On the glossy paper 10 minutes after the image was formed, the ink was sticky at the black portion, but the glossy paper was not damaged when peeled off (judgment: Δ).

On the other hand, in the first embodiment in which the coating device 30 is operated and in the second embodiment in which the drying device 40 is operated, in any case, the ink is adhered to the clear file at the portion of the black image on the glossy paper. I never did. Obviously, removing the glossy paper from the clear file did not damage the glossy paper.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, the powder used in the first embodiment is not limited to a colorless and transparent powder having a porous structure.
Any material can be used as long as it can prevent the ink from being adhered to other objects while being supplied on the surface of the paper P.

[0041]

As described above, since the image forming apparatus of the present invention has the above-described configuration and operation, the image formed by the recording liquid formed on the image forming medium can be stabilized. And a high quality image can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a main part of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a coating apparatus incorporated in the printer of FIG.

FIG. 3 is a schematic diagram showing a drying device incorporated in the printer of FIG. 1;

FIG. 4 is a diagram plotting data obtained by comparing an image output when the coating device in FIG. 2 or the drying device in FIG. 3 is operated with an image output when these devices are not operated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ink-jet printer, 2 ... Housing, 4 ... Conveyance roller, 6 ... Paper feed tray, 8 ... Discharge tray, 12 ... Paper supply roller, 14 ... Conveyance guide, 16 ... Discharge roller, 18 ... Guide roller, 20 ... print head, 22 ... post-processing device, P ... paper.

Claims (8)

[Claims] An image forming unit configured to discharge a recording liquid toward the image forming medium and form an image using the recording liquid on the image forming medium; and an image formed using the recording liquid by the image forming unit. An image forming apparatus comprising: a powder supply unit configured to supply powder to a surface of an image forming medium and to prevent the image from touching another object. 2. The image forming apparatus according to claim 1, wherein the powder is colorless and transparent. 3. The image forming apparatus according to claim 2, wherein the powder has a porous structure. 4. A conveying means for conveying an image forming medium, and a recording liquid is discharged toward the image forming medium conveyed by the conveying means, and an image is formed on the image forming medium by the recording liquid. An image forming unit, a storage unit that is provided downstream of the image forming unit in the transport direction and stores a powder having a colorless and transparent porous structure, and records the powder stored in the storage unit by the image forming unit. A supply member that supplies the surface of the image forming medium on which the image is formed with the liquid, and an adjustment mechanism that adjusts a supply amount of the powder by the supply member, and supplies the powder whose supply amount is adjusted to the surface. And a powder supply means for preventing the image formed on the surface from touching another object. 5. The supply member is rolled on a surface of an image forming medium conveyed by the conveyance unit on which an image is formed, and holds the powder in the storage portion on a peripheral surface thereof, and rotates the supply member. The image forming apparatus according to claim 4, further comprising an application roller that applies the held powder to the surface by performing the operation. 6. The image forming apparatus according to claim 4, wherein said powder supply means is selectively operated only when a mode for supplying powder to the image forming medium is selected. . 7. A conveying means for conveying an image forming medium, and a recording liquid is discharged toward the image forming medium conveyed by the conveying means to form an image by the recording liquid on the image forming medium. An image forming unit, provided on the downstream side in the transport direction from the image forming unit, and applying heat to the surface of the image forming medium on which the image is formed by the recording liquid by the image forming unit, thereby forming an image by the recording liquid An image forming apparatus, comprising: a drying unit that dries the toner. 8. The image forming apparatus according to claim 7, wherein the drying unit is selectively operated only when a mode for drying an image using a recording liquid is selected.