JP2002192799A - Protective means for recording head and recorder comprising protective means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a head against damage due to paper jam while facilitating sheet discharging processing. SOLUTION: In the way of carriage of a recording sheet, planarity of the sheet (floating from a platen, corner fold, cockling, etc.), is detected and a head is retreated quicker than the sheet carrying speed so that the sheet does not abut against the head face. At the same time, carriage is stopped. Since a countermeasure is taken before paper jam takes place, the head is not damaged and sheet discharging processing is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus using a method such as ink jet, thermal transfer, and heat sensitivity, and more particularly to a recording apparatus having a full line type head.

[0002]

2. Description of the Related Art An ink jet recording apparatus performs recording by discharging ink toward a recording medium from a plurality of ink discharge ports in accordance with a control signal.

The ink-jet recording system can easily reduce the size of the apparatus as compared with other recording systems, for example, an electrophotographic system, and can produce a low-cost, high-quality recording apparatus. Is being developed.

Among them, a full-line type ink jet recording head in which recording elements are arranged in a number corresponding to a recording width is superior to a conventional serial type head in that recording can be performed at extremely high speed. Is expected as a high-speed recording technology.

[0005]

SUMMARY OF THE INVENTION In a recording apparatus,
A so-called jam may occur in which a recording medium such as paper or an OHP film is not conveyed normally and is jammed in a conveyance path.

If a paper jam occurs in the recording head, the paper may be conveyed while the paper is sandwiched between the ink discharge port surface of the head and the platen, so that the discharge port surface may be damaged or dust may be pushed into the discharge port. There is.

In the case of an inexpensive serial type exchangeable head, it is sufficient to replace the head when the head is damaged. However, in the case of a full line type head, the head itself is expensive. It takes a lot of trouble.

Although various measures have been taken to eliminate the jam itself, the probability of occurrence of the jam has been reduced. However, in the event that an unexpected situation occurs, such as when a user inserts paper that is out of specification, the jam still occurs. The danger is high.

A full-line type high-speed recording apparatus is more expensive, and means for preventing head damage due to an accident is required in order not to lower the operation rate.

[0010]

SUMMARY OF THE INVENTION The present invention has means for detecting a recording paper just before a recording paper jams near the head in order to prevent damage to the head, and for retracting the recording head based on the detection result. It is characterized by the following.

The detection of a jam is meaningless even if the jam is detected after the head has been damaged.

Therefore, in the present invention, the jam detecting means measures the flatness of the recording paper (floating from the platen) just before the recording paper reaches the recording head.

When the flatness of the paper is greater than a specified value,
In other words, if the paper breaks or bends and the head and its vicinity are likely to jam and cause a jam, stop the paper transport and simultaneously retract the recording head away from the paper to prevent the jam itself. Even if the paper becomes wrinkled to some extent, the head is prevented from being damaged by preventing the head from touching.

The head is retracted at a speed higher than the recording paper transport speed, and when the bent or broken paper reaches the head face, the retraction is already completed to prevent the head from being damaged.

[0015]

1 to 3 are multiple views showing a first embodiment of the present invention. FIG. 1 shows a standby state of the printer of the present invention.

The printer has print heads 101, 102, 103, 104
With yellow (Y), magenta (M), and cyan, respectively.
(C) and black (K) printing.

Each print head has a resolution of 600 dpi,
It is a full-line inkjet head with 7,200 effective nozzles, and its driving frequency is 4kHz.

The cap 201 can move in the left-right direction on FIG.

When the printer is on standby, the cap moves to the lower part of the print heads 101 to 104, and the print heads 101 to 104 descend so as to press their nozzle surfaces against the cap to prevent the ink of the nozzles from drying.

FIGS. 2 and 3 show the state of the printer of the present invention during printing.

At the time of printing, the print heads 101 to 104 once rise, and after the cap 201 moves and comes off the face surface of the print head, the print head descends to a position having a predetermined distance from the recording paper. When the print signal is sent, the recording paper 500 is supplied onto the transport belt 400 from a paper feeding device (not shown). The transport speed of the recording paper is 170 m / S.

The recording paper 400 is attracted to the transport belt and passes under the print head, and the recording head ejects ink based on a print signal to perform recording. The recording paper on which all printing has been completed is stored in a stacker (not shown).

Here, it is assumed that there is a paper sheet fed with its leading end folded, such as the recording paper 500 in FIG. A laser sensor 300 is provided in front of the print head 104, and a light emitting unit and a light receiving unit are installed so as to face in the longitudinal direction of the print head, that is, in the paper width direction.

The height of the laser beam is set higher than the face of the head, so that the normally transported recording paper does not block the laser beam, but the folded or bent recording paper hits the head. When transported at a height, the laser light is blocked, and a change in the laser light is detected by a light receiving unit.

When abnormal conveyance is detected, the conveyance of the recording paper is immediately stopped, and a lock (not shown) supporting the entire head unit 200 is released, and the entire head unit is retracted upward by about 5 mm by the force of the spring 402 (see FIG. 4, FIG. 5).

Since the recording paper has not yet been jammed, it is sufficient to retract the recording paper to such a distance that the floating does not touch the head.

The retreat speed of the head unit needs to be equal to or higher than the transport speed of the recording paper in order to reliably protect the head face from being damaged by the recording paper. In this embodiment, since the recording paper conveyance speed is 170 mm / s, the strength of the spring 402 is adjusted so that the head unit is retracted at a speed of 200 mm / s.

FIG. 6 shows a second embodiment of the present invention. In the present embodiment, sensors for detecting the floating of the paper are installed one by one in front of each print head.

In this way, even if the recording paper printed by the first and second heads swells with ink and causes cockling and rises higher than the head face, this is detected and jams are prevented beforehand. can do.

Further, in the above embodiment, the head unit with the head, the cap and the like is evacuated and the recording paper path is completely opened to prevent the jam, but if the head can be moved quickly enough. Alternatively, only the head may be retracted as in the normal capping operation.

Further, it is not necessary to evacuate all the heads, but it is also possible to evacuate only the head which is likely to hit the recording paper.

The means for detecting the floating of the recording paper may be any means other than the laser as long as it can detect the floating of the recording paper over the entire head width.

[0033]

According to the present invention, a paper floating which may cause a so-called jam, in which a recording paper is caught and jammed between a head and a belt, is detected, and the head unit is retracted so that the jam does not occur. Thus, even if printing stops, the recording paper can be easily removed without damaging the head or jamming the paper.

[Brief description of the drawings]

FIG. 1 is a compound diagram showing a first embodiment.

FIG. 2 is a composite diagram showing a state in which a recording sheet is conveyed.

FIG. 3 is a diagram of FIG. 2 viewed from a direction in which a recording sheet enters.

FIG. 4 is a diagram illustrating a state in which the head unit is retracted.

FIG. 5 is a view of FIG. 4 as viewed from a direction in which the recording paper enters.

FIG. 6 is a composite diagram showing the second embodiment.

[Explanation of symbols]

 101 to 104: print head 200: head unit 201: cap 300: sensor 301: laser beam 400: transport belt 401: drive roller 402: spring 500: recording paper

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C058 AB04 AC07 AD04 AE02 AE09 AF27 AF31 GA07 GB11 GB30 GB47 GB52 GB53 GE16 2C064 CC05 EE07 FF06 3F048 AA05 AB01 BA11 BB02 BB10 BD07 CC16 DA06 DB11 DC05 EA15 EB22

Claims (8)

[Claims] 1. A recording head protection device comprising: means for detecting a recording paper just before a paper jam occurs in the vicinity of the recording head; and means for increasing a distance between the recording head and the recording paper based on a detection result. Means and a recording apparatus using the protection means. 2. The recording head protection device according to claim 1, wherein the detection device detects flatness of the recording paper (paper floating from the platen). 3. The recording head protection means according to claim 1, wherein the moving speed when the distance between the recording head and the recording paper is increased is equal to or faster than the recording paper conveyance speed. Recording device using protection means. 4. When the distance between the recording head and the recording paper is increased,
2. The recording head protection means according to claim 1, wherein the head is retracted, and a recording apparatus using the protection means. 5. When the distance between the recording head and the recording paper is increased,
2. The recording head protection means according to claim 1, wherein the recording paper (platen) side is retracted, and a recording apparatus using the protection means. 6. When the distance between the recording head and the recording paper is increased,
2. The recording head protecting means according to claim 1, wherein the paper conveyance is stopped, and a recording apparatus using said protecting means. 7. The recording head protecting means according to claim 1, wherein the recording head is a line head, and a recording apparatus using the protecting means. 8. The recording head protecting means according to claim 1, wherein the detecting means is located immediately before each of the plurality of heads.