JPH0472698B2 - - Google Patents

Abstract

PURPOSE:To accurately perform the temp. control of ink by preventing the transmission of the heat of a heating means to a carriage, by forming an air layer between the ink heating means provided to the bottom part of an ink jet head and the carriage for mounting said head. CONSTITUTION:To the side of an ink jet head unit 1 equipped with an ink sump., an orifice, an ink jet energy imparting means, an ink temp. detection means and a temp. control means and having an ink heating means 15 provided to the bottom part thereof, a protruded piece 1a is provided and a recessed part 10a corresponding to the heating means 15 of the carriage 10 mounting the head unit 1 is provided. By this recessed part 10a, an air layer is formed between the carriage 10 and the head unit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a liquid jet recording apparatus, and more particularly to a liquid jet recording apparatus equipped with a head unit that performs recording by ejecting liquid by heating it.

[Prior art]

FIG. 1 shows an outline of a liquid jet recording apparatus equipped with a conventional recording head of this type.

In the figure, the reference numeral 1 denotes a head unit that has a built-in liquid jet recording head, which ejects liquid such as ink supplied from the main tank 2 through the tube 3 as flying droplets to record on the recording paper 4. Let's do it.

Also, the reference numeral 5 is a discharge recovery pump that is used when liquid discharge failure or non-discharge occurs, and this pump 5 sucks liquid from an orifice (not shown) in the head unit 1 through a tube 6. to recover the discharge operation. At this time, the liquid in the head unit 1 is also sucked from the tube 7.

The sucked liquid is led to a waste liquid reservoir 8 and stored.

Note that the cap designated by numeral 9 should be used when liquid jet recording is not performed for a long period of time or when transporting the device.
This is to prevent the liquid in the head unit 1 from drying out and to prevent foreign matter such as dust from getting mixed into the liquid, and is fitted to the tip of the head unit 1.

Moreover, the one indicated by the symbol 10 is the head unit 1.
11 is a platen.

A liquid jet recording device having such a structure has low noise compared to an impact type recording device such as a wire dot recording device, and does not require post-processing such as fixing, so it has become popular as an effective recording device.

There are two types of liquid jet recording devices of this type: on-demand type and continuous type.

On-demand type devices eject droplets only when a recording command is received, while continuous types eject droplets at a constant frequency and record the electric field applied to the space in which the droplets fly. This type of device records by changing the trajectory of droplets according to commands, and collects and circulates droplets that are not related to recording.

On-demand type equipment is in high demand because it has a simpler structure than continuous type equipment.

On the other hand, the physical properties of the liquid used for recording, such as viscosity and surface tension, change depending on the temperature. Since the size of the recording dots on the recording paper changes, the recording quality or image quality is not stable depending on the usage conditions of the apparatus, which is an obstacle to high-quality recording.

In order to eliminate these drawbacks, a temperature detection means is provided to detect the environmental temperature in which the device is placed and the temperature of the droplet forming means, and the temperature can be adjusted by heating part or all of the droplet forming means based on the signal. Attempts have been made to provide compensation and constant temperature of the droplet forming means.

Conventional examples having such a structure are shown in FIGS. 2 and 3.

In the example shown in FIGS. 2 and 3, the head unit 1 is constructed as a multi-orifice type having a plurality of orifices 12. In the example shown in FIGS.

This orifice 12 is formed at the tip of a liquid flow path 13, and each liquid flow path 13 is accommodated at the bottom of an independently partitioned liquid reservoir 14.

Each liquid reservoir 14 is supplied with liquid such as ink of the same color or different colors.

Further, a flat heating means 15 is fixed to the bottom of each liquid reservoir 14.

Further, near the orifice 12 of the liquid flow path 13, an energy generator such as a piezoelectric element is attached along the liquid flow path.

On the other hand, select one of the liquid reservoirs and turn on the temperature sensor 17.
is installed to detect the temperature of the liquid in the reservoir.

Based on this structure, the temperature of the liquid is detected by the temperature sensor 17, and the liquid is heated by the heater 15 to maintain a constant temperature.

The head unit 1 having such a structure is provided with a protruding piece 1a on its side surface as shown in FIG. 3, and is fixed to the carriage 10 with screws through this protruding piece 1a.

However, when such a mounting structure is adopted, the heat of the heating means 15 escapes to the carriage 10 side, and the head unit 1 and the carriage 10 are regarded as one large heat capacity body, so the device is activated and the temperature compensation circuit is activated. Even when the system is activated, it takes a long time to reach the target control temperature, resulting in a long waiting time for the device.

〔the purpose〕

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology, and it is an object of the present invention to provide a liquid jet recording device configured so that the waiting time due to temperature compensation is short and no heat is wasted by the heating means. The purpose is

〔Example〕

Hereinafter, details of the present invention will be explained based on embodiments shown in the drawings.

FIGS. 4 and 5 illustrate one embodiment of the present invention, and the same parts as in FIGS. 1 to 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, a recess 10a having approximately the same area as the heating means 15 is formed on the upper surface of the carriage 10 at a portion where the head unit 1 is fixed.

The head unit 1 is mounted via the projection 1a so that the heating means 15 is located above the recess 10a, as shown in FIG.

When installed in this way, an air layer is formed under the heating means 15 by the recess 10a, so
This air layer blocks heat and prevents the carriage 10.
Since no heat is transferred to the side and the amount of heat of the heating means 15 is used only to raise the temperature of the head unit 1, the target control temperature for temperature compensation is quickly reached, the standby time is short, and there is no loss time.

In the above embodiment, the recess is provided on the carriage side, but a recess may be provided on the bottom surface of the head unit 1, and the heating means may be provided in the recess.

〔effect〕

As is clear from the above description, according to the present invention, a structure is adopted in which an air layer is provided between the heating means provided on the lower surface of the head unit and the carriage in which the head unit is installed. The heat is used to raise the temperature of the head unit and does not escape to the carriage side, allowing the target temperature for temperature compensation to be reached quickly and the standby time to be shortened.

[Brief explanation of the drawing]

Figures 1 to 3 explain the conventional structure.
Figure 1 is a perspective view of the main parts of the liquid jet recording device;
Figure 3 is a perspective view of the head unit, Figure 3 is a perspective view showing the installed state of the head unit, Figures 4 and 5 illustrate an embodiment of the present invention, Figure 4 is an exploded perspective view, and Figure 5 is a perspective view of the head unit. is a front view of the installed state. 1...head unit, 10...carriage,
12... Orifice, 13... Liquid flow path, 14...
Liquid reservoir, 15... heating means, 16... energy generator, 17... temperature detection means.

Claims (1)

[Claims] 1. A liquid reservoir containing a liquid used for recording;
a liquid flow path provided with an energy generator for receiving the liquid from the liquid reservoir and discharging the liquid from the orifice; a temperature detection element provided in a part of the liquid reservoir; a head unit having a heating means whose temperature is controlled by a detection signal of the element on the bottom surface of the liquid reservoir; and a carriage on which the head unit is mounted and which fixes the side of the head unit on which the heating means is disposed; A liquid jet recording apparatus characterized in that an air layer is provided between the heating means of the head unit and the carriage on which the head unit is mounted.