JPH0740533A - Ink jet printer - Google Patents

Abstract

PURPOSE:To improve the dependability of capping by eliminating the variation of a head position at a capping position. CONSTITUTION:A fixing part 4 for fastening a carriage 20 at a position where a cam face 22b indicating the highest value of eccentricity of an eccentric cam 22 for gap adjustment allowed to come into contact with a guide plate 15, comes into contact with the guide plate 15, or at a position where the cam face 22b leaves the guide plate 15, is installed at a capping position. The fixing part 40 has a gradient face 41 which comes into contact with the pin 28 of the carriage to allow the carriage to rotate around a guide shaft and a control part 43 which controls the further rotation of the carriage allowed to rotate by the gradient face.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to ink jet printers. In particular, the present invention relates to a technique capable of obtaining a highly reliable capping state in an inkjet printer having a gap adjusting function for adjusting a distance between an ink ejection surface of an inkjet head and a printing surface of a recording paper.

[0002]

2. Description of the Related Art Generally, in an ink jet printer, as shown in FIG. 4, an ink jet head (hereinafter also simply referred to as a head) 1 is orthogonal to a moving direction of a recording paper S (a direction orthogonal to the paper surface of FIG. 4). While moving in the direction X, ink droplets are ejected from the ink ejection surface 1a to print on the recording paper S. Since a predetermined number of nozzle openings are provided on the ink ejection surface 1a and ink droplets are ejected from the nozzle openings, if the nozzle openings are not sealed during non-printing, the ink may be evaporated by evaporation of the ink solvent. Viscosity increase, ink drying, dust adhesion, etc. occur, which causes printing defects.

Therefore, this type of ink jet printer has conventionally been provided with a capping means for sealing the nozzle opening during non-printing.

As the capping means, there are JP-A-59-103762, JP-A-1-125239,
Various structures are known as seen in Japanese Patent Application Laid-Open No. 5-8398, but in any case, the basic structure is such that the head 1 does not perform the printing operation as shown in FIG. At the standby position HP, the cap 2 made of an elastic member is brought into contact with the ink ejection surface 1a of the head 1 with a predetermined urging force F. In the figure, A is a printing area and B is a non-printing area. When the head 1 enters the non-printing area B from the printing area A and stops at the standby position HP, the cap 2 located at the bottom in FIG. Is moved upward by a mechanism (not shown) to contact the ejection surface 1a of the head to seal the nozzle opening. Reference numeral 3 is a support member for the cap 2, and 4 is a spring for applying a biasing force F.

On the other hand, in the ink jet printer as described above, the head 1 is set so that the gap G between the printing surface Sa and the ink ejection surface 1a of the head 1 is constant even if the thickness of the recording paper S is different. It is desirable to have a gap adjusting means for displacing it in a direction (arrow Y1 or Y2 direction) to move away from or approach the recording surface Sa of the recording paper. ing.

[0006]

The ink jet printer provided with the capping means and the gap adjusting means as described above has the following problems.

When the head 1 is displaced in the direction of the arrow Y1 or Y2 by the gap adjusting means in accordance with the thickness of the recording paper S, the position of the head 1 with respect to the capping means also changes when the head 1 stops at the standby position HP. To do. That is, the distance L in FIG. 4 changes.

When the distance L fluctuates, the urging force F obtained by the spring 4 also fluctuates, resulting in the following problem (a).
(B) was occurring.

(A) When the head 1 is displaced in the Y1 direction, the distance L becomes long and the biasing force F becomes small, so that the adhesion between the cap 2 and the ink ejection surface 1a of the head 1 deteriorates. There was a problem.

(B) When the head 1 is displaced in the Y2 direction, the distance L becomes shorter, the urging force F becomes larger, the cap 2 is easily deformed, and the adhesion with the ink ejection surface 1a is also poor. There was a problem of becoming.

That is, there is a problem that the reliability of the capping state is lowered in any case.

Even if the capping means is not provided with the spring 4 for urging the cap, the cap itself made of an elastic member functions as a spring member, so that the above problems still occur.

It is an object of the present invention to solve the above problems and to provide a highly reliable ink jet printer having a gap adjusting function for adjusting the distance between the ink ejection surface of the head and the printing surface of the recording paper. The purpose is to obtain a capping state.

[0014]

In order to achieve the above object, an ink jet printer according to a first aspect of the invention ejects ink droplets from an ink ejection surface while moving in a direction orthogonal to a moving direction of a recording sheet. An inkjet head that prints on recording paper, and a gap adjustment that adjusts the distance between the ink ejection surface of the inkjet head and the printing surface of the recording paper by displacing the inkjet head in a direction that moves away from or approaches the recording surface of the recording paper. An ink jet printer having means and a capping means for bringing a cap made of an elastic member into contact with an ink ejection surface of the ink jet head by a biasing force of a spring member when the ink jet head is in a standby position where the ink jet head does not perform its printing operation. , The ink jet adjusted by the gap adjusting means. Characterized by comprising a fixing means for fixing interval constant for capping means of the ink jet head in the standby position regardless of the distance between the ink ejection face and the recording sheet on the printed surface of the Toheddo.

The "urging force of the spring member" as used herein includes the elastic force of the cap itself.

An ink jet printer according to a second aspect is the ink jet printer according to the first aspect,
The ink jet head is a carriage rotatably supported around the guide shaft by a guide shaft provided in a direction orthogonal to the moving direction of the recording paper and a guide plate provided in parallel with the guide shaft. Is installed in
The gap adjusting means is configured by bringing a cam surface of an eccentric cam rotatably provided on the carriage into contact with the guide plate, and the fixing means is a cam surface having the largest eccentric amount of the eccentric cam. Is constituted by a fixing portion for fixing the carriage at a position where it comes into contact with the guide plate or a position where this cam surface is separated from the guide plate.

An ink jet printer according to a third aspect is the ink jet printer according to the second aspect,
The guide shaft and the guide plate are composed of a single guide shaft and a single guide plate arranged above the moving recording paper, the eccentric cam contacts the upper surface of the guide plate, and the fixing portion is An inclined surface that contacts a part of the carriage when the carriage moves toward the standby position and rotates the carriage around the guide axis, and a restricting portion that restricts further rotation of the carriage rotated by the inclined surface. It is characterized by having and.

[0018]

According to the ink jet printer of the first aspect, the ink jet head moves in a direction orthogonal to the moving direction of the recording paper, and ink droplets are ejected from the ink ejection surface to print on the recording paper. The gap between the ink ejection surface of the inkjet head and the printing surface of the recording paper can be adjusted by displacing the inkjet head in a direction of moving away from or approaching the recording surface of the recording paper by the gap adjusting means. When in the standby position where the printing operation is not performed, the cap made of the elastic member is brought into contact with the ink ejection surface of the inkjet head by the biasing force of the spring member by the capping means.

When the capping operation is performed, the fixing means fixes the ink jet head at the standby position regardless of the distance between the ink ejection surface of the ink jet head and the print surface of the recording paper adjusted by the gap adjusting means. Since the distance to the capping means is fixed, the biasing force of the spring member is constant.

Therefore, a stable capping state can be obtained, and a highly reliable capping state can be obtained.

According to a second aspect of the present invention, in the ink jet printer according to the first aspect, the ink jet head is provided with a guide shaft provided in a direction orthogonal to a moving direction of the recording paper, and the guide shaft. Is mounted on a carriage that is rotatably supported around the guide shaft by a guide plate that is provided in parallel with, and the gap adjusting means is a cam surface of an eccentric cam that is rotatably provided on the carriage. Since the eccentric cam is rotated, the carriage rotates around the guide shaft, whereby the ink ejection surface of the inkjet head and the printing surface of the recording paper are rotated. The spacing is adjusted.

The fixing means is composed of a fixing portion for fixing the carriage at a position where the cam surface having the largest eccentricity of the eccentric cam contacts the guide plate or at a position where the cam surface is separated from the guide plate. Therefore, even if the eccentric cam is rotated to any position, it is always fixed to the fixed position.

Therefore, a stable capping state can be obtained, and a highly reliable capping state can be obtained.

According to a third aspect of the present invention, there is provided the ink jet printer according to the second aspect, wherein the guide shaft and the guide plate are a single guide shaft and a single guide shaft arranged above the moving recording paper. A guide plate, the eccentric cam contacts the upper surface of the guide plate,
The fixed portion is an inclined surface that abuts a portion of the carriage when the carriage moves toward the standby position and rotates the carriage around the guide axis, and further rotation of the carriage that is rotated by the inclined surface. Since it has a restricting part for restricting, the gap adjusting means and the fixing means can be realized with a simple structure.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the ink jet printer according to the present invention, and is a partially omitted perspective view showing the internal structure.

In the figure, 10 is a lower case of the printer, 11 is a main frame, and 12 and 13 are side frames supporting the main frame 11.

Reference numeral 20 denotes a carriage, which is provided around the guide shaft 14 by a guide shaft 14 supported by the side frames 12 and 13, and a guide plate 15 also supported by the side frames 12 and 13 in parallel with the guide shaft 14. It is rotatably supported. This carriage 20
It is driven by a carriage motor (not shown) via a timing belt and moves in the directions of arrows X1 and X2. An inkjet head 21 is mounted on the carriage 20.

Reference numeral 16 is a paper feed roller, 17 is a paper feed roller,
Reference numeral 18 is a paper discharge roller, and 19 is a paper discharge tray.

The recording paper is fed into the printer from below the paper discharge tray 19 by the paper feed roller 16 as shown by the arrow a, wound around the paper feed roller 17 and reversed, and is discharged by the paper discharge roller 18 in the arrow direction. As shown in FIG.
Discharged on top. Then, in the process from the paper feed roller 17 to the paper discharge roller 18, printing is performed by the head 21 that moves in the directions of arrows X1 and X2.

On the front side of the carriage 20, as shown in FIG. 2, an eccentric cam 22 constituting a gap adjusting means.
Are rotatably provided. Reference numeral 23 denotes a shaft integrally provided on the carriage, and the shaft 23 rotatably supports the eccentric cam 22. An operation lever 24 is formed integrally with the eccentric cam 22. Reference numeral 25 is an elastic piece integrally formed with the eccentric cam 22, and the tip of the elastic piece engages with the protrusion 26 or 27 formed on the front surface of the carriage with a click feeling, thereby making it possible to perform the operation as shown in FIG. The position of the eccentric cam 22 rotated as shown in FIG. The eccentric cam 22 has a first cam surface 22a with a relatively small eccentricity and a second cam surface 22b with a relatively large eccentricity. When the eccentric cam 22 is rotated in the state shown in FIG. 2A, the first cam surface 22a comes into contact with the upper surface of the guide plate 15 so that the carriage 20 and the head 21 move to the recording sheet S1 as shown by an arrow Y2. When it is displaced so as to approach, and when it is rotated to the state shown in FIG. 7B, the second cam surface 22b comes into contact with the upper surface of the guide plate 15, and the carriage 20 and the head 21 record as shown by arrow Y1. It is displaced so as to move away from the paper S2.

Therefore, when the eccentric cam 22 is set as shown in FIG. 2A, it is in a state suitable for printing on a relatively thin recording sheet S1, and when it is set as shown in FIG. 2B, it is relatively thick. The state is suitable for printing on the recording sheet S2.

In the figure, 21a is an ink ejection surface of the head 21, 28 is a pin integrally provided on the carriage for engaging with and disengaging a fixing means 40 described later, and 30 is a guide plate arranged below the recording paper. Is.

1 to 3, reference numeral 40 denotes a fixing portion which constitutes a fixing means and is provided at a position on the guide plate 15 corresponding to the standby position HP of the head.

The fixing portion 40 has an inclined surface 41, a horizontal surface 42 connected to the inclined surface 41, and a restriction portion 43 formed on the hook above the horizontal surface 42.

The inclined surface 41 is shown in FIG.
Regardless of the state in which the carriage 20 is positioned downward as shown in FIG. 9A and the state in which it is positioned upward as shown in FIG.
When the carriage is moved toward the standby position HP as shown in (4), it is provided at a position where it abuts the pin 28 of the carriage to rotate the carriage around the guide shaft 14 (in the direction of arrow Y1). That is, when the carriage 20 moves in the direction of the arrow X2, the pin 28 abuts against the inclined surface 41 and is lifted up, and since the pin 28 is formed integrally with the carriage, the pin 28 reaches the horizontal surface 42. The front side of the carriage is lifted around the guide shaft 14.

Then, as shown in FIGS. 2C and 3, when the pin 28 reaches the horizontal plane 42, the pin 28 is positioned below the restricting portion 43 and even if the carriage 20 is further rotated, the pin 28 is rotated. When 28 comes into contact with the restricting portion 43, it is in a non-rotating state (fixed state).

Height h of the horizontal surface 42 from the upper surface of the guide plate
Is set to such a height that the cam surface (the second cam surface 22b in this embodiment) having the largest eccentric amount of the eccentric cam 22 is separated from the guide plate 15. The height h can be appropriately set within a range until the second cam surface 22b comes into contact with the guide plate 15.

In FIG. 2C, 50 is a capping means having the same structure as the conventional one, and when the head 21 is at the standby position HP, the ink ejection surface 21 of the head 21.
A cap 2 made of an elastic member is brought into contact with a by an urging force F of a spring 4 to seal the nozzle opening. Although the capping means 50 is schematically shown in the figure, any capping means may be adopted as long as it has the basic structure described above.

According to the ink jet printer as described above, when the capping operation is performed, the fixing portion 40 is used regardless of the distance between the ink ejection surface 21a of the head adjusted by the eccentric cam 22 and the printing surface of the recording paper. Since the distance between the head 21 and the capping means 50 at the standby position HP is fixed, the biasing force F of the spring member 4 becomes constant.

Therefore, a stable capping state can be obtained, and a highly reliable capping state can be obtained.

Further, the guide shaft 14 and the guide plate 15
Is composed of a single guide shaft and a single guide plate arranged above the moving recording paper, the eccentric cam 22 is brought into contact with the upper surface of the guide plate 15, and the fixed portion 40 makes the carriage 20 stand by. When it moves toward the position, it contacts the pin 28 of the carriage and rotates the carriage around the guide shaft 14. An inclined surface 41 and a regulation that restricts further rotation of the carriage 20 rotated by the inclined surface 41. Since it has the portion 43, the gap adjusting means and the fixing means can be realized with a simple structure.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0044]

According to the present invention, when the capping operation is performed, the standby position is fixed by the fixing means regardless of the distance between the ink ejection surface of the ink jet head and the printing surface of the recording paper adjusted by the gap adjusting means. Since the distance between the inkjet head and the capping means is fixed at a constant value, the biasing force of the spring member becomes constant.

Therefore, a stable capping state can be obtained, and a highly reliable capping state can be obtained.

[0046]

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an inkjet printer according to the present invention, and is a partially omitted perspective view showing an internal structure.

2A, 2B, and 2C are operation explanatory views.

FIG. 3 is an enlarged perspective view of a main part.

FIG. 4 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 S Recording paper F Biasing force HP Standby position 2 Cap 4 Spring member 14 Guide shaft 15 Guide plate 20 Carriage 21 Inkjet head 21a Ink ejection surface 22 Eccentric cam 22a Cam surface 22b Cam surface 28 Pin 40 Fixing portion 41 Sloping surface 42 Horizontal surface 43 Regulation Part 50 Capping means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41J 25/30 G

Claims (3)

[Claims] 1. An ink jet head for ejecting ink droplets from an ink ejection surface to print on the recording paper while moving in a direction orthogonal to the moving direction of the recording paper, and an ink jet head for the recording surface of the recording paper. Gap adjusting means for adjusting the distance between the ink ejection surface of the inkjet head and the printing surface of the recording paper by displacing the inkjet head away from or toward the inkjet head, and the inkjet head when the inkjet head is in the standby position where the printing operation is not performed. An ink-jet printer having a cap made of an elastic member and abutting against the ink ejection surface by a biasing force of a spring member, wherein the ink ejection surface of the ink-jet head adjusted by the gap adjusting means and recording paper printing. In the standby position regardless of the distance from the surface An inkjet printer provided with a fixing means for fixing a distance between a cuddle head and a capping means to be constant. 2. The ink jet head is rotatable around the guide shaft by a guide shaft provided in a direction orthogonal to the moving direction of the recording paper and a guide plate provided parallel to the guide shaft. Is mounted on a carriage supported by, and the gap adjusting means is configured by bringing a cam surface of an eccentric cam rotatably provided on the carriage into contact with the guide plate, and the fixing means. 2. The fixing portion for fixing the carriage at a position where the cam surface having the largest eccentric amount of the eccentric cam contacts the guide plate or at a position where the cam surface separates from the guide plate. Inkjet printer. 3. The guide shaft and the guide plate are composed of a single guide shaft and a single guide plate arranged above a moving recording sheet, and the eccentric cam abuts an upper surface of the guide plate, The fixed portion is an inclined surface that abuts a part of the carriage when the carriage moves toward the standby position and rotates the carriage around the guide axis, and further rotation of the carriage that is rotated by the inclined surface. The inkjet printer according to claim 2, further comprising a restriction unit that restricts the above.