JPH08324055A - Static electricity generator and ink jet image forming apparatus - Google Patents

Abstract

PURPOSE: To stabilize and enhance printing capacity without especially complicating constitution. CONSTITUTION: A Teflon fiber sheet 107 is attached to the rear surface of a movable carriage 102 having a printing head 101 mounted thereon so as to come into contact with printing paper 110 and a wool fiber sheet 108 is attached to the belt 103 moving the carriage 102 so as to come into contact with the platen 109 on which the printing paper 110 is placed. When the carriage 102 is moved by the belt 103 to perform printing, negative charge is generated in the Teflon fiber sheet 107 and positive charge is generated in the printing paper 110 while positive charge is generated in the wool fiber sheet 108 and negative charge is generated in the platen 109 and, therefore, the printing paper 110 is stably held to the platen 109 in a close contact state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet image forming apparatus for performing printing by reciprocating a print head and a static electricity generating apparatus.

[0002]

2. Description of the Related Art Conventionally, in an ink jet printer which prints by reciprocal movement of a print head, a schematic diagram of FIG. 7 is used for the purpose of improving the accuracy of landing of ink droplets ejected from the print head on a print sheet. As shown, print head 71 and print paper 7 on platen 72
The distance of 3 is around 5 mm, which is extremely close.

[0003]

As shown in FIGS. 7 and 8, the conventional ink jet printer has a print head 71.
Since the print sheet 73 and the print sheet 73 are close to each other, if the print sheet 73 is slightly floating from the platen 72, the landing points of the ink droplets are displaced and the print quality is degraded. The delicate structure of the ink ejection port may be damaged by sliding on the print paper, resulting in permanent destruction. Also,
It also causes a paper jam (jam) in the paper transport system from the printing process to the print paper discharging process.

As a first means for solving this problem, a paper holding mechanism using a mechanical member has been proposed. That is, as shown in FIG. 8A, when the print paper 73 is fed to the print position in the arrow direction, the suspension plate 81 and the suspension plate 82 are flipped up, and when the paper feeding is completed, the sheet shown in FIG. As shown, the suspension plate 81 and the suspension plate 82 are pushed down, and the print sheet 73 is lightly pressed onto the platen 72 by a spring (not shown) having an appropriate spring constant to eliminate the floating of the print sheet 73.

As a second means, a method has also been proposed in which the platen 72 and the print sheet 73 are charged with electric charges having different polarities so that the platen 72 and the print sheet 73 are brought into close contact with each other by electrostatic force.

However, the above-mentioned first means has a drawback that it requires a complicated mechanical mechanism and the apparatus structure becomes complicated. In addition, the above-mentioned second means requires a charger composed of a high-voltage transformer and a charging line, which not only complicates the apparatus structure but also increases the power supply capacity of the apparatus.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and a static electricity generating device which does not particularly complicate the structure of the device, and a static electricity improving device which is provided with the static electricity generating device, can improve printing performance in a stable manner. The present invention aims to provide the inkjet image forming apparatus.

[0008]

In the static electricity generating apparatus according to the present invention, at least one of adjacent members forming the apparatus is movable, and static electricity is generated by friction between the members during operation of the apparatus. Static electricity generating means to generate,
It is an object of the present invention to achieve the above-mentioned object by a configuration including a charging unit that charges a member with static electricity generated by the static electricity generation unit.

An ink jet image forming apparatus according to the present invention includes a print head having a plurality of nozzles for ejecting ink, forms a band-shaped image by scanning the print head, and connects the band-shaped images to one page. An inkjet image forming apparatus for printing a minute image, comprising static electricity generating means for generating static electricity by friction between a member that is movable during printing and a fixed member in the scanning means that scans the print head. It is an object of the present invention to achieve the above-mentioned object by a configuration including a charging unit that charges a predetermined member with the static electricity generated by the static electricity generation unit.

[0010]

With the above structure, for example, a combination of members that generate static electricity due to friction between wool and Teflon is provided, and each member is attached to the movable member and the fixed member of the ink jet printer to generate static electricity due to the friction between them. The generated static electricity makes it possible to bring the platen into close contact with the print paper, thus solving the above problems.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A static electricity generating apparatus and an inkjet image forming apparatus (printer) according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a main configuration of an ink jet printer which is an embodiment of the present invention. A part of the carriage 102 on which the print head 101 is mounted is fixed to a part of a belt 103, and is guided by a guide 105 by the rotation of a pulley 104 which is interlocked with a motor (not shown), and the arrow A or the arrow B is used. Move in the direction of. At a position facing the pulley 104, a pulley 106 pulled by a spring (not shown) with an appropriate tension in the direction of arrow C is provided, and the belt 103 has a constant tension.

A Teflon fiber sheet 107 is attached to the carriage 102, while a wool fiber sheet 108 is attached to a part of the belt 103 (a position directly below the carriage 101 in FIG. 1). Reference numeral 109 is a platen, and a printing paper 110 is placed on the platen 109.
Is transported.

First, the structure in the vicinity of the carriage 102 in FIG. 1 is shown in the perspective view of FIG.

In the figure, the same members as those described above are designated by the same reference numerals. The Teflon fiber sheet 107 is attached to a stay 201 made of insulating plastic, which is attached to a part of the carriage 102, the direction of the fibers is perpendicular to the horizontal plane as shown in the figure, and the tips of the fibers are in the platen. It touches 109. That is, the print paper 11
When 0 is fed and the printing operation is performed, the tip of the Teflon fiber of the Teflon fiber sheet 107 and the printing paper 110 are rubbed against each other, the Teflon fiber sheet 107 is charged with − (minus), and the printing paper 110 is charged with + (plus). ) Is charged. It is a well known fact that Teflon has a negative polarity of static electricity generated by friction with other substances. In this way, the print paper 11
0 is charged with +.

FIG. 3 shows the appearance of the vicinity of the wool fiber sheet 108 in FIG. A plastic plate 301 made of insulating plastic is attached to the belt 103, and a wool sheet 108 is attached to the plastic plate 301.
The direction of the fibers of the wool is perpendicular to the horizontal plane as shown in FIG. 3, and the tips of the fibers are in contact with the platen 109. That is, when the printing operation is performed, the belt 103 moves in the direction of the arrow, and the tip of the wool sheet 108 and the platen 1
09, the wool fiber sheet 108 has a positive (+) charge, and the platen 109 has a negative (-).
Is charged. It is a well known fact that the polarity of static electricity generated by the friction of wool with other substances is +.

The platen 109 is made of two kinds of materials as shown in the perspective view of FIG. That is, a thin Teflon sheet 302 made of Teflon is arranged at a position where the wool ends touch, and a glass fiber sheet 303 made of a glass fiber having a small dielectric constant is arranged at other places. It has become. It is a well known fact that the polarity of static electricity generated by friction between wool and Teflon is + for wool and − for Teflon, but the electrostatic charge due to the combination of wool and Teflon is large. In this way, the platen 109, particularly the Teflon sheet 302, is negatively charged in a concentrated manner.

Next, the operation of actually printing will be described.

FIG. 4 is an explanatory view of the portion of the carriage 102 as seen from directly above. At the start of printing, the carriage 102
Is located at the start position, moves in the direction of arrow X in the drawing when printing is started, ejects ink at a required position from the nozzle array 41 arranged on the print head 101, and forms an image on the print paper 110. Do. Carriage 101 and wool sheet 10 at the start position
The positional relationship of No. 8 is shown in FIG.

The nozzle array 41 arranged on the print head 101 has 128 nozzles and has a printing resolution of 400 dp.
If it is i, it has a print width of about 8 mm.

An image having a width of 8 mm is formed by the movement of the carriage 102, and the Teflon fiber sheet moves in the direction of the arrow X while contacting the hatched portion of the print paper 110. Therefore, static electricity is generated due to friction, and as described above, positive charges are concentrated on the hatched portion. The width of hatching is about 8
mm. At the same time, the wool sheet 108 is the platen 1.
While moving in contact with the Teflon sheet 302 of No. 09, it moves in the direction of arrow Y. Therefore, also in this case, static electricity is generated due to friction, and as described above, the negative electric charge is concentrated on the portion of the Teflon sheet 302. Printing is performed up to the end position, the carriage 102 moves in the direction of arrow Y, and the first printing operation ends. The positional relationship between the carriage 101 and the wool sheet 108 at the end position is shown in FIG.

Before the carriage 102 returns to the start position and the second printing operation is started, the printer is
A print motor 110 (not shown) pulls out the print paper 110 in the direction of arrow Z shown in FIG. 4 by the print width (about 8 mm).
At this time, the first printing operation causes the print paper to
The charged portion is overlapped with the negatively charged Teflon sheet 302 in the platen 109, and the print paper 110 and the platen 109 are in close contact with each other at a position where the nozzle array 41 in the print head 101 passes. No floating occurs.

In this manner, the printing of the width of 8 mm is sequentially performed to form the desired image, and then the print paper 110 is printed out by the paper discharge motor (not shown).

In the above embodiment, since the print paper 110 and the platen 109 are not charged during the first printing operation, a pre-operation may be added to the printing sequence. That is, the feeding of the print paper 110 is stopped at a position 8 mm short of the print start position, and the print paper 110 is advanced by 8 mm after the carriage reciprocates once.
If the first printing operation is performed, the contact between the print paper 110 and the platen 109 can be realized from the first printing operation.

(Other Embodiments) In the above embodiment,
Although the generation of static electricity due to friction was used for the close contact between the printing paper and the platen, the present invention is not limited to the usage of only the above embodiment. Hereinafter, other examples will be described.

Conventionally, in an ink jet type printer, when ink is ejected from a print head, a very small part of an ink droplet becomes vapor, and the ink vapor floats around the carriage. This vapor liquefies again due to a slight change in the environment and stains around the carriage, and in the worst case, these stains often adhere to the print paper.

In another embodiment of the present invention, a method of utilizing static electricity due to friction is adopted as a means for solving this problem.

In another embodiment, the structure around the carriage is substantially the same as the structure described in the previous embodiments.
However, the static electricity generated by the friction between the Teflon fiber sheet 107 and the print paper 110 is intended to charge the ink droplets with a- (minus) electric charge.

That is, the Teflon fiber sheet 1 in FIG.
The-charge generated in 07 is introduced to the print head 101 via a conductor (not shown). Thus, the print head 101
Ink droplets ejected from are charged with a negative electric charge. Of course, the amount of electric charge that is charged is not so large as to affect the landing position of the ink droplet.

Further, as shown in the perspective view of the main part of FIG. 6, a drum 61 which rotates in accordance with the rotation of the pulley 104 is provided near the pulley 104 in FIG. Drum 6
A Teflon fiber sheet 62 is wound around 1, and the tip of the Teflon fiber is in contact with the wool sheet 63 as shown in the figure. That is, the drum 61 rotates every time the carriage 102 performs a printing operation, the Teflon fiber sheet 62 and the wool sheet 63 generate static electricity due to friction, the Teflon fiber sheet 62 has a negative charge, and the wool sheet 63 has a positive charge. Is charged. The positive charge on the wool sheet 63 is
Through the conductor 64, the ink absorber 65 having an appropriate dielectric constant is also charged with +.

With the above arrangement, the negatively charged ink vapor generated during printing is attracted to the ink absorber 65 in the vicinity of the home position to prevent stains around the carriage. However, since the ink vapor has a negative electric charge, it does not adhere to the Teflon fiber sheet 62 charged with the same negative electric charge, but may directly adhere to the wool sheet 63. It is desirable that the members other than the absorber 65 are surrounded by a member having a low dielectric constant.

Needless to say, if the structure shown in FIG. 6 is additionally arranged near the pulley 106 on the end position side, a further effect can be expected.

[0033]

As described above, according to the present invention,
Like the carriage of an inkjet printer, static electricity is intentionally generated by friction between a member that moves during operation and a fixed member near the movable member, and a positive charge is applied to the print paper and a negative charge is applied to the platen. By charging, the static electricity is generated without particularly complicating the configuration of the printer, and the static electricity improves the contact between the print paper and the platen, improving the accuracy of the ink droplet landing position,
Also, the frequency of paper jams is greatly reduced. Further, by adopting the configuration described in the other embodiments, it is possible to minimize the scattering of ink vapor that causes ink stains on the apparatus, and it is possible to prevent stains on the print paper. .

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a main configuration of an inkjet printer according to an embodiment.

FIG. 2 is a perspective view around a carriage on which a print head according to an embodiment is mounted.

FIG. 3 is a perspective view of a member for charging the platen of one embodiment with static electricity.

FIG. 4 is an explanatory diagram of the carriage as viewed from above.

FIG. 5 is an explanatory diagram showing start positions and end positions of main members.

FIG. 6 is a perspective view showing the configuration of the main part of another embodiment.

FIG. 7 is a schematic diagram showing a main configuration of a conventional inkjet printer.

FIG. 8 is an explanatory diagram of a main part operation of a conventional inkjet printer.

[Explanation of symbols]

 41 Nozzle Array 61 Drum 62 Teflon Fiber Sheet 63 Wool Sheet 64 Conductor 65 Absorber 71 Print Head 72 Platen 73 Print Paper 101 Print Head 102 Carriage 103 Belt 104 Pulley 105 Guide 106 Pulley 107 Teflon Fiber Sheet 108 Wool Sheet 109 Platen 110 Print Paper 201 Stay 301 Plastic board 302 Teflon sheet 303 Glass fiber sheet

Claims (2)

[Claims] 1. Static electricity generating means for generating static electricity by friction between said members during operation of the device, wherein at least one of adjacent members constituting the device is movable, and said static electricity generating means. A static electricity generating device, comprising: a charging unit that charges the member with the generated static electricity. 2. An inkjet image comprising a print head having a plurality of nozzles for ejecting ink, forming a band-shaped image by scanning of the print head, and connecting the band-shaped images to print an image for one page. The forming apparatus includes static electricity generating means for generating static electricity by friction between a member that is movable during printing and a fixed member in the scanning means that scans the print head, and is generated by the static electricity generating means. An inkjet image forming apparatus comprising: a charging unit that charges a predetermined member with static electricity.