JPH05278281A - Printer - Google Patents

Abstract

PURPOSE:To enable a recording medium to be fed without deteriorating recording quality in non-contact with a recording surface of the recording medium by a method wherein a connecting passage between a clearance for transmitting sucking force generating a recording medium sucking means and the sucking means is provided. CONSTITUTION:An ink jet head 5 together with a carriage 4 prints on printing paper 6 while reciprocating along a guide shaft 3. Besides, a paper feed roller 13A further carries the printing paper in a paper feed direction. Then, when a tip of the paper 6 reaches a small diameter part 18 of a paper roller 13B, the paper 6 receives downward force by a chamber 25 wherein its pressure is lowered with a suction fan 25, and the force generates frictional force between the paper 6 and the roller 13B. Rotation of the roller 13B is transmitted to the paper 6 through the frictional force, and paper feed on the downstream in the paper feed direction of the head 5 is carried out. When printing has advanced further, a rear end of the paper 6 comes out from the rollers 13A and 16, and the paper is fed only with the roller 13B. Paper feed after printing can be carried out thus in non-contact with a printing surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus which holds and conveys a recording medium and records on the recording medium.

[0002]

2. Description of the Related Art Conventionally, as a paper feeding mechanism of this type of printing apparatus, a printing paper is nipped by a paper feeding roller which is rotationally driven by a driving means and a pressing roller which is pressed by the paper feeding roller and is rotatable. A method of feeding a sheet by rotating a sheet feeding roller has been widely used.

As an example, FIGS. 3, 4, and 5 show an ink jet printer. A sheet feeding unit 41 for stacking printing sheets and feeding the sheets to the platen 40 is provided, and the platen is placed at a predetermined distance from a printing head 43 for printing while moving in a direction perpendicular to the sheet feeding direction indicated by an arrow 42. 40 is provided, and a paper feed roller 44 is provided upstream and downstream of the print head 43 in the paper feed direction.
A pair of rotatable movable pressing rollers 46, which are pressed and supported by the leaf springs 45, are provided on each pair. The paper feed roller 44 is rotationally driven by a paper feed motor 47 via a drive pulley 48, a timing belt 49, and a paper feed pulley 50. And further downstream,
Paper ejection unit 5 for storing printed paper after printing
1 is provided.

When the printing paper 52 is fed onto the platen 42 in the printing apparatus having such a structure, first, the printing paper 52 is nipped by the paper feeding roller 44 and the pressing roller 46 located upstream of the printing head 43, Presser roller 46
Paper feed roller 44 and printing paper 5 generated by pressing
The paper is fed using the frictional force between 2 and
When the print position of 0 is fed to the position just below the print head 43, the print head prints on the print paper 52 while reciprocating in the direction perpendicular to the paper feed direction indicated by the arrow 42. After that, when the paper is further fed, the printing paper 52
Is clamped by the paper feed roller 42 and the pressing roller 46 located downstream of the print head 43, and the paper is fed. And
Finally, the paper is fed only by the paper feed roller 42 and the pressing roller 46 downstream of the print head 43.

[0005]

However, in the printing apparatus configured as described above, since the pressing surface of the printing paper 52 after printing is pressed by the pressing roller 46 located downstream of the printing head 43, the printing apparatus is not quick-drying. When a printing device using a non-existent ink or a paper which does not easily penetrate the ink, for example, a polyester film used for OHP is used, the ink in the printing portion is transferred to the pressing roller 46 to be contaminated, and then the paper is fed. This time, the ink is transferred from the presser roller 46 to the printing surface of the printing paper to stain the printing surface, or the printing paper 5
On the other hand, the lump of the ink forming the image on the surface 2 was crushed to deteriorate the print quality. Further, the position of the downstream pressing roller 46 has to be farther than the printing position in order to allow time for the ink to dry after printing and for the ink to sufficiently penetrate, and as a result, the size of the apparatus is wasted. There was also the problem that it would become too big. For this reason, the printable range that the printer attaches to the printing paper is narrowed in the direction perpendicular to the paper feeding direction, and the press roller 46 is pressed.
It has also been done so as not to press the printing part.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a printing apparatus that feeds a recording medium without deteriorating the quality of recording performed on the recording medium. I am trying.

[0007]

In order to achieve this object, a printing apparatus of the present invention is provided with a print head for recording on a recording medium and a print head which is arranged so as to face the print head. A platen and a portion of the outer peripheral surface of the circumferential portion, which is located on the opposite side of the platen from the print head and holds and conveys the recording medium, protrudes from the platen to the print head side, and the peripheral axis from the outer peripheral surface. Paper feed roller having one or more recesses cut out in the direction, a gap provided between the outer surface of the recess and the platen, and the gap from the side opposite to the print head with respect to the platen. To suck the recording medium and attract the recording medium to the outer peripheral surface of the recording medium feed roller, and to transmit the suction force generated by the recording medium suction means to the recording medium. Wherein and a flow path connecting the gap between the recording medium suction means.

[0008]

According to the printing apparatus of the present invention having the above-mentioned structure, the recording medium is sucked through the gap between the platen and the concave portion of the recording medium feeding roller so that the recording medium is placed on the outer peripheral surface of the circumferential portion of the recording medium feeding roller. attract. Utilizing the frictional force between the recording medium feed roller and the recording medium generated by that force,
Transport the recording medium. Therefore, the recording medium can be conveyed without touching the recording surface after recording.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet printer as an embodiment of the present invention will be described below with reference to FIGS.

A platen 2 is attached to the frame 1 of the printer body.
And a guide shaft 3 provided in parallel with it is supported at both ends. A carriage 4 is attached to the guide shaft 3.
However, it is movably supported in parallel to the platen 2 with a predetermined distance from the platen 2. An inkjet head 5 is mounted on the carriage 4 at a position facing the platen 2, and printing is performed on the printing paper 6.

A carriage drive motor 7 as a drive source of the carriage 4 is arranged on the outer wall 1A of the frame 1, and a carriage drive pulley 8 attached to the carriage drive motor 7 and an arrow 9 on the outer wall 1A. A timing belt 11 for a carriage is stretched between an idle pulley 10 mounted on an outer wall 1B of a frame 1 arranged so as to face in a direction orthogonal to the sheet feeding direction. A part of the carriage timing belt 11 is fixed to the carriage 4 by a belt pressing member 12, and the driving force of the carriage driving motor 7 is passed through the carriage driving pulley 8, the carriage timing belt 11 and the belt pressing member 12. Transmitted to the carriage 4. As a result, the carriage 4 is moved in parallel with the platen 2 along the guide shaft 3.

An arrow 9 is attached to the ink jet head 5.
An upstream paper feed roller 13A is disposed on the upstream side in the paper feed direction indicated by. This upstream paper feed roller 13
A support member 14 is disposed above A at both ends thereof being supported by the frame 1, and a pressing roller 16 is provided at the tip of a leaf spring 15 attached to the support member 14 to apply a predetermined pressure to the paper feed roller 13A. It is provided so as to abut. Further, downstream of the inkjet head 5 in the paper feed direction, a downstream paper feed roller 13B causes a part of the outer peripheral surface of the circumferential portion thereof to project from the platen 2 to the inkjet head 5 side, and Gap 17 between 2
It is provided with. The paper feed roller 13B includes two small-diameter portions 1 having a smaller roller diameter than the other portions.
8 is provided with a gap 19 wider than the gap 17 with the platen 2.

The paper feed rollers 13A, 13B are fixed to the paper feed roller shafts 20A, 20B, and the paper feed pulleys 21A, 2 are provided at one ends of the paper roller shafts 20A, 20B.
1B are fixed coaxially. A paper feed motor 22 serving as a drive source thereof is fixed to the outer wall of the frame 1, and a timing belt 24 is stretched between the paper feed drive pulley 23 attached to the paper feed motor 22 and the paper feed pulleys 21A and 21B. Has been done. Therefore, the driving force of the paper feed motor 22 is the same as the paper feed drive pulley 23, the timing belt 24, and the paper feed pulley 2.
It is transmitted to the paper feed rollers 13A and 13B via 1A and 21B and the paper feed roller shafts 20A and 20B.

Downstream paper feed roller 1 below platen 2
A chamber 25 is formed by the frame 1 and the platen 2 in the vicinity of 3B, and a suction fan 27 driven by a suction fan drive motor 26 is attached to the lower end of the chamber 25. The suction fan 27 is mainly used for the paper feed roller 13 of the platen 2.
When air is sucked into the chamber 25 through the gap 19 provided directly above the small diameter portion 18 of B and the printing paper 6 covers the small diameter portion 18 as the paper is fed, the pressure in the chamber is lowered and the printing paper 6 is lowered. Aspirate into.

Next, the paper feeding operation of the printing apparatus having the above construction will be described. The printing paper 6 sent to the platen 2 from the paper feeding unit similar to that of the conventional technique is nipped by the paper feeding roller 13A and the pressing roller 16, and is conveyed to just below the inkjet head 5 as the paper feeding roller 13A rotates. Then, the inkjet head 5 prints on the print paper 6 while reciprocating along the guide shaft 3 together with the carriage 4, and at the same time, the paper feed roller 13A further conveys the print paper in the paper feed direction. Then, the leading end of the printing paper 6 is the paper roller 13B.
When it reaches the small-diameter portion 18 of the
The chamber 25 whose pressure is lowered by 7 receives a downward force, and the force is applied to the printing paper 6 and the paper feed roller 1.
A frictional force is generated between 3B. The rotation of the paper feed roller 13B is transmitted to the print paper 6 through this frictional force, and the paper is fed downstream in the paper feed direction of the inkjet head 5. Further, as the printing progresses, the trailing edge of the printing paper 6 is fed by the paper feeding roller 13A and the pressing roller 1.
6, the sheet is fed by only the sheet feed roller 13B, and is conveyed to the sheet discharge unit similar to the conventional technique.

As described above, according to the present invention, it is possible to feed the paper after printing without touching the printing surface of the printing paper 6 with a member. Therefore, the ink which is not quick-drying or the polyester film which is hard to soak into the ink can be used. Even if such printing paper is used, the paper can be fed without impairing the printing quality of the image printed over the entire printing paper. Further, since the downstream paper feed can be brought close to the inkjet head, the device can be downsized.

In the above-mentioned embodiment, an example in which the present invention is applied to an ink jet printer has been described. However, the present invention is not limited to this, and a printing device using a liquid ink at the time of printing, for example, an ink jet plotter or a pen plotter is of course used. That is, a thermal transfer printer, an impact dot printer, and a printing device that performs post-processing such as fixing processing after transferring an image formed by an image forming body on printing paper, for example, an electrophotographic printer, an electronic printer. The same effect can be obtained with a photographic plotter. Further, in the above-described embodiment, the case where the gap 19 between the platen 2 and the small diameter portion 18 is wider than the gap 17 between the platen 2 and the downstream paper feed roller 13B has been described. May be narrower than. Further, the chamber 25 of the above-described embodiment includes the entire downstream paper feed roller 13B, but may include only the vicinity of the small diameter portion 18.

[0018]

As is apparent from the above description, the printing apparatus of the present invention can feed the recording medium without touching the recording surface of the recording medium after recording, so that the recording is performed over the entire surface of the recording medium. Even with a recorded image, it is possible to obtain a good recording result without deterioration in quality.

[Brief description of drawings]

FIG. 1 is a side sectional view of a printer to which the present invention is applied.

FIG. 2 is a perspective view showing the overall structure of the printer.

FIG. 3 is a perspective view showing the appearance of a conventional printer.

FIG. 4 is a side sectional view of a prior art printer.

FIG. 5 is a perspective view showing the overall structure of a conventional printer.

[Explanation of symbols]

 2 Platen 5 Inkjet head 13B Paper feed roller 18 Small diameter part 19 Gap 25 Chamber 27 Suction fan

Claims (1)

[Claims] 1. A print head for recording on a recording medium, a platen which is arranged so as to face the print head and guides the recording medium, and a recording medium which is located on the opposite side of the platen from the print head. A recording medium feed roller having a part of the outer peripheral surface of the peripheral part for holding and conveying the platen protruding from the platen to the print head side, and having one or more recesses cut out from the outer peripheral surface in the circumferential axis direction, A gap provided between the outer surface of the recess and the platen, from the side opposite to the print head with respect to the platen,
Recording medium suction means for sucking the recording medium through the gap and attracting the recording medium to the outer peripheral surface of the recording medium feed roller, and transmitting the suction force generated by the recording medium suction means to the recording medium. In order to achieve this, the printing apparatus is provided with a flow path that connects the gap and the recording medium suction means.