JPS62122773A - Head-down operation for recording head - Google Patents

Abstract

PURPOSE:To effectively prevent a recording sheet from being contaminated, by turning down a recording head to a point immediately before an ink sheet makes contact with the recoding sheet, and after stopping the head at the position for a predetermined period of time or slightly moving it toward a head-up position, and then driving the head to a head-down position at which it presses against the recording sheet through the ink sheet therebetween. CONSTITUTION:When a thermal head 4 is driven to move from a head-up position toward a head-down position, a tension is exerted on both sides of an ink ribbon 11, and the ink ribbon 11, and the ink ribbon 11 is slightly paid out in the direction of an arrow. This driving in a direction toward the head-down position is carried out to a point immediately before the ink ribbon 11 makes contact with a sheet 2. Then, the head 4 is slightly moved toward the head-up position or is stopped for a predetermined period of time, whereby the ink ribbon 11 supplied with the tension at the time of the movement toward the head-down position is paid out under inertia, and is made to sag. Accordingly, the ink ribbon 11 is prevented from being moved in a feeding direction at the moment the thermal head 4 makes contact with the sheet 2, and the sheet is prevented from being contaminated due to friction with the ink ribbon 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an operating method when lowering a recording head in an image recording apparatus.

[Prior art]

A recording device such as a printer or facsimile is a device that records on a recording sheet (a recording medium such as paper or a thin plastic plate) by driving a recording head based on a print data signal. Serial types that perform main scanning are widely used.

Furthermore, there are various recording methods such as an inkjet method, a wire dot method, and a thermal method.

Among these, the thermal type has dot forming means consisting of a plurality of electrothermal transducers (heating elements) on the front surface of the recording head (thermal head), and the dot forming means is pressed against the sheet and slides. It is configured to perform heating recording by driving based on a print data signal.

There are two types of thermal recording devices: one is a thermal type that uses a heat-sensitive sheet (a sheet that develops color when heated) and records without an ink ribbon, and the other is a thermal transfer type that uses an ordinary sheet and performs transfer recording via an ink ribbon. There is a thermal transfer recording device).

In this type of recording apparatus, the recording head is mounted so as to be driven to swing between a head-down position in which it comes into pressure contact with the recording sheet and a head-up position in which it separates from the recording sheet.

That is, in a carriage scanning type thermal transfer recording device, at the time of recording, the thermal head is lowered and slid in pressure contact with the recording sheet via the ink ribbon, and is driven based on print data.

On the other hand, when recording is stopped and a recording sheet is inserted and removed or a ribbon feeder is attached or removed, and when the thermal head is skipped or returned during recording, the thermal head is isolated from the recording sheet for a desired period of time. Driven to head-up position.

By the way, in a conventional method for operating a thermal head in a downward position, a method of driving the thermal head from a head-up position to a head-down position all at once has been adopted.

However, such a conventional head-down operation method has a problem in that the ink ribbon moves between the sheet and the thermal head at the moment the thermal head contacts the sheet, staining the sheet when the head is down.

In other words, when tension is applied to the ink ribbon on the surface of the thermal head when the head is down, the ink ribbon is fed out from the winding side and the supply side of the ribbon force center as the head moves down. If the feeding load differs due to differences in the side core system or ribbon amount, the feeding amount from both sides will differ and the ink ribbon will move in the feeding direction at the moment the thermal head contacts the sheet, causing dirt on the sheet due to rubbing of the ink ribbon. arise.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive head-down operation method that can solve the problems of the prior art and effectively prevent staining of a recording sheet when the head is down.

〔overview〕

When lowering the recording head, the present invention lowers the recording head until just before the ink sheet contacts the recording sheet,
Next, by stopping at the immediately preceding position for a predetermined period of time or moving it slightly upward, and then driving it to the down position where it comes into pressure contact with the recording sheet via the ink sheet,
This aims to achieve the above objectives.

〔Example〕

The present invention will be specifically described below with reference to the drawings.

FIG. 1 shows the main parts of a thermal transfer recording apparatus suitable for implementing the method of the present invention, and FIGS. 2 to 4 show cross sections in various states of FIG. 1.

1 to 4, a thermal head 4 mounted on a carriage 3 records on a recording sheet 2 bank-amplified on a platen 1. In addition, the illustrated platen 1
is roller-shaped and also serves as a sheet conveyance roller.

The carriage 3 is movably mounted along a guide shaft 5 installed parallel to the platen 1, and includes a stepping motor 6, a driving pulley 7, a driven pulley 8, and a belt wound around these pulleys and coupled to the carriage 3. It is reciprocated by a drive system consisting of 9 parts.

The thermal head/board 4 has a plurality of heating elements (for example, 24F [lil resistors) arranged in a vertical line, and is positioned at a head-down position (Fig. 4) where it is in pressure contact with the recording sheet 2 and when it is separated from the recording sheet 2. It is attached to the carriage 3 so as to be swingable between the hand-assembly positions (FIG. 2).

A ribbon spool 10 for feeding an ink sheet (ink ribbon) 1) to the front surface of the thermal head 4 is detachably set on the carriage 3.

The ink ribbon 1) inside the ribovka cent 10 is
or navel-down position), the thermal head 4 is moved in a predetermined direction by a ribbon drive shaft (not shown) provided in the carriage 3.
It is wound in synchronization with the movement of.

In FIGS. 2 to 4, the thermal head 4 is pivotally supported on the carriage 3 so as to be able to swing around a bin 12,
An arm 14 for swinging the thermal head 4 is pivotally supported on the bin 12 via a spring 13.

On the other hand, the carriage 3 is equipped with a head up/down drive motor 25 for driving the thermal head 4 away from (up) or into pressure contact (down) with respect to the platen l. 16
is arranged to drive the rotation.

The tip of the arm 14 is brought into contact with the cam surface 16A of the wheel cam 16, and the rotational position of the arm 14 around the pin 12 is regulated by the rotational position of the wheel cam 16. It is designed to regulate the head-up and head-down positions.

However, according to the present invention, when the thermal head 4 is operated from the head-up position (FIG. 2) to the head-down position (FIG. 4) at the time of starting recording, etc., first, the ink that is fed out in the down direction with the thermal head 4 is The thermal head 4 is lowered to the position (Fig. 3) just before the ribbon 1) contacts the sheet 2, and then the thermal head 4 is lowered for a predetermined period of time (
(e.g. 1 to 3 seconds) Stop the thermal head 4 at this position, or move the thermal head slightly upward, and then move the thermal head 4 to the head-down position (Fig. 4), i.e., the ink ribbon 1). It is controlled so that it is driven to a position in which it comes into pressure contact with the sheet 2 via.

5 to 8 schematically show each operation of the head-down operation according to the present invention.

FIG. 5 shows the head-up position of the thermal head 4,
When the ink ribbon 1) is driven in the head-down direction (direction toward the sheet 2) from this state, tension is applied to both sides of the ink ribbon 1), or due to its inertia, the reels 17.1 on both sides are
The ink ribbon above 8 will be slightly fed out in the direction of the arrow.

This drive in the head-down direction is continued until just before the ink ribbon 1) contacts the sheet 2, as shown in FIG.

Next, as shown in FIG. 7, the thermal head 4 is moved slightly in the head-up direction (in the opposite direction) to loosen the ink ribbon 1) as shown.

Note that the movement of the thermal head 4 in the downward direction as shown in FIG. 7 is omitted, and instead, the thermal head is held in the immediately preceding position shown in FIG. 6 for a predetermined period of time (for example, 2 to 3 seconds).
You can also leave it stopped. That is, by stopping the thermal head 4 at the previous position for a predetermined time,
The ink ribbon 1) which has been subjected to tension when moving in the downward direction is fed out by its inertia force, and the ink ribbon 1) can be made slack in the same way as shown in FIG.

After the ink ribbon 1) is fed out in this manner, the thermal head 4 is driven to the head down position and set in a state where it is pressed against the sheet 2 via the ink ribbon 1), as shown in FIG.

According to the head-down operation method described above with reference to FIGS. 2 to 4 and 5 to 8, the ink ribbon 1) temporarily stops the thermal head 4 just before it contacts the sheet 2. Or, after stopping, the head is moved slightly upward, and then the head is lowered, so that the ink ribbon 1) can be fed out to the front of the thermal pad to eliminate tension before the head is lowered. It is possible to prevent the ink ribbon 1) from moving (shifting) in the feeding direction at the moment of contact with the sheet 2, and it is possible to prevent the sheet from being stained due to rubbing of the ink ribbon 1). .

FIG. 9 is a block diagram of a system for controlling the head-down operation described above.

In FIG. 9, a CPU (microprocessor) 20 of the recording apparatus is connected to a host 21 such as a computer or a word processor, and receives print data signals and necessary command signals (commands).

The CPU 20, via the driver (drive circuit) 22,
carriage drive motor 23, sheet conveyance motor 24,
It controls various drive systems such as the head amplifier down drive motor 25 and the ribbon drive motor (ribbon winding switching means when using the movement of the carriage 3) 26, and also controls the thermal head 4 based on the print data signal from the host 21. The dot forming means (heating element) is driven.

The operation of the recording device is controlled based on a program stored in a ROM attached to the CPU 20.

FIG. 10 is a flowchart illustrating the procedure of the head-down operation in the control system of FIG. 9.

In FIG. 10, when preparations such as insertion of sheet 2 are completed and recording is started in step 100, step 101
Then, the thermal head 4 is driven in the downward direction until just before the platen 1 (just before the ink ribbon 1 contacts the sheet 2).

After driving until just before the head is down, step 102
Then, the thermal head 4 is moved slightly back in the head-up direction, or left stopped at the position just before the head-down for a predetermined period of time, thereby making the ink ribbon 1) in front of the thermal head 4 slack. .

Thereafter, in step 103, the thermal head 4 is driven to the head-down position and brought into pressure contact with the sheet 2 via the ink ribbon 1).

Therefore, the process proceeds to step 104, where one line is recorded, and after one line has been recorded, the process proceeds to step 105, where the head is raised, and in step 106, the sheet 2 is fed by one line.

Thereafter, in step 107, it is determined whether or not recording has ended. If it has not ended, the process returns to step 101 and the aforementioned operations are repeated.

If recording has been completed, the process enters a standby state for the next process in step 108.

The head-down operation method of the recording head explained above is as follows.
The present invention can be similarly applied to both bidirectional recording in which recording is performed while the thermal head 4 is reciprocating, and unidirectional recording in which recording is performed only while the thermal head 4 moves in one direction.

Note that the present invention can be similarly applied to a full-line type image recording apparatus (such as a line printer) in which the recording head is of a fixed type.

Further, as long as the recording apparatus performs recording with an intervening ink sheet, it can be similarly applied to recording apparatuses other than thermal transfer type, such as wire dot type recording apparatus.

〔effect〕

As is clear from the above description, according to the present invention, there is provided a head-down operation method for a recording head that can reliably prevent staining of the recording sheet due to rubbing between the ink sheet and the recording sheet when the head is down. Ru.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the main parts of a recording device suitable for carrying out the present invention, and FIGS. 2 to 4 are sectional views and cross-sectional views of the recording device of FIG. Figure 5~
FIG. 8 is a plan view schematically showing each state of the recording apparatus shown in FIGS. 1 to 4 during head-down operation, and FIG. 9 is a block diagram of a control system suitable for carrying out the method of the present invention. , FIG. 10 is a flowchart illustrating the operating procedure of the control system of FIG. 9. 2-1---recording sheet, 3---carriage,
4---1 recording head (thermal head), 10...-
・-・Ribbon cassette, 20・---CPU,
25・------Hend-abutment-down drive motor. Figure 1 Figure 5 Figure 6 Figure 7 Figure 8 Figure 10

Claims (1)

[Claims] (1) In an image recording apparatus that records on a recording sheet according to image information, when lowering the recording head, is the ink sheet lowered until just before it contacts the recording sheet, and then stopped at this position for a predetermined period of time? Alternatively, a head-down operation method for a recording head is characterized in that the recording head is moved slightly in an upward direction and then driven to a down position in which it comes into pressure contact with a recording sheet through an ink sheet.