JP3635754B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus that performs printing by spraying hot melt ink on paper.
[0002]
[Prior art]
A communication device such as a facsimile device and an information processing device such as a personal computer usually have a recording device capable of recording these data on paper so as to record data consisting of characters and figures as visual information. In this recording device, various printing methods such as impact method, thermal method, ink jet method, etc. have been adopted, but in recent years, it is excellent in quietness, can be printed on paper of various materials, and has clear image quality. Inkjet recording apparatuses using hot-melt inks that can be obtained are attracting attention.
[0003]
Conventionally, the above-described ink jet recording apparatus has a recording head provided with a direct current heater for heating hot melt ink that is solidified at room temperature, and the hot melt ink is heated and melted by supplying electric power to the direct current heater. Thus, the hot melt ink is ejected from the nozzles of the recording head that is subjected to main scanning and sprayed onto the paper while maintaining the molten state. And according to this configuration, when the hot melt ink is sprayed on the paper, the melted hot melt ink is rapidly cooled and changed to a solid state, so that there is no bleeding on the paper like liquid ink, An extremely good image quality can be obtained.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, if the heat capacity of the DC heater is set to such an extent that the hot melt ink is maintained in a molten state, the hot melt ink will be turned on when the recording apparatus is turned on and started up. A large waiting time is caused until the solid state is changed to the molten state due to the heating of the heater. Therefore, in order to shorten the waiting time when starting up the apparatus, it is necessary to adopt a DC heater having a large heat capacity. In this case, the capacity of the DC power supply for supplying power to the DC heater is also increased. However, there is a problem that the parts cost is excessive as it is necessary only when the apparatus is started up.
[0005]
On the other hand, if an AC heater that does not require a DC power supply is used in place of the DC heater, it is possible to prevent an increase in the component cost due to the power supply as described above. Since reinforced wiring such as double insulation that satisfies various safety standards (for example, UL standards) is required, when the AC heater is main-scanned together with the recording head, scanning is likely to be unstable due to the reinforced wiring. There is. Further, in this case, since a commercial power source or the like is directly connected to the power supply path, there is a problem that malfunction is likely to occur due to external noise during main scanning.
[0006]
Accordingly, an object of the present invention is to provide an ink jet recording apparatus capable of completing the start-up of the apparatus in a short time without causing the above problems.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 is an ink jet recording which performs printing by ejecting the hot melt ink while performing main scanning on a recording head provided with a heating means for heating and melting the hot melt ink. In the apparatus, the heating means includes an AC heater having a heat capacity sufficient to melt the hot melt ink and a DC heater having a minimum heat capacity necessary for maintaining the molten state of the hot melt ink. AC power supply means that is detachable from the AC heater, engages the AC heater when the recording head is located at a home position, and supplies power to the AC heater, and at least the recording head includes DC power supply means for supplying power to the DC heater when not in the home position is provided.
[0008]
Thus, when the recording head is at the home position, the hot melt ink is heated by the AC heater having a sufficient heat capacity to melt the hot melt ink, so that the hot melt ink is rapidly heated to be in a molten state. Therefore, the start-up of the apparatus can be completed in a short time. In the main scanning, the DC heater for heating the hot melt ink is set to the minimum heat capacity necessary for maintaining the molten state of the hot melt ink. The parts cost of the supply means can be reduced. Furthermore, during the main scanning, the AC heater and the AC power supply means are separated from each other, so that the scanning stability of the recording head is not reduced by, for example, the reinforcing wiring of the AC power supply means, and the AC power supply is not performed. No malfunction occurs in the printing operation due to external noise contained in the power of the means.
[0009]
The invention of claim 2 is characterized in that the DC power supply means of claim 1 does not supply power to the DC heater when the recording head is located at a home position. As a result, unnecessary power consumption can be further suppressed.
[0010]
According to a third aspect of the present invention, the heating means according to the first aspect has a flat base member made of an insulating material, and the AC heater and the DC heater are respectively formed on both surfaces of the base member. It is characterized by having. Thereby, since the AC heater and the DC heater are respectively formed on both surfaces of the base member, the heating means can be reduced in size.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
As shown in FIG. 2, the ink jet recording apparatus according to this embodiment includes a lower cover 1 and an upper cover 2 that serve as a casing. On the rear side of the upper cover 2, paper feeding mechanisms 3 and 4 that can receive and store a large number of sheets 20 are provided on the front and rear sides. In the vicinity of the lower ends of these paper feed mechanisms 3 and 4, paper feed rollers 5 and 6 are disposed, respectively, and the paper feed rollers 5 and 6 are paper 20 accommodated in the paper feed mechanisms 3 and 4, respectively. Is sent out to the transport path 7.
[0012]
The transport path 7 includes a first transport roller 8, a second transport roller 9, a paper discharge tray unit 10, and a paper discharge port 1a in this order from the paper feed mechanism 3 or 4 side. While the paper 20 is moved quantitatively or continuously in the direction of the arrow (sub-operation direction) by the two transport rollers 8 and 9, the paper 20 is discharged from the discharge port 1a to the outside of the apparatus.
[0013]
A printing mechanism main body 11 is disposed on the upper cover 2 side of the conveyance path 7. The printing mechanism main body 11 includes a recording head 12, a carriage 13 joined to the recording head 12, a guide member 14 that supports the carriage 13 movably in a main scanning direction perpendicular to the sub-scanning direction, and a carriage 13. And a travel mechanism (not shown) that reciprocates along the guide member 14 in the main scanning direction (main scanning).
[0014]
As shown in FIG. 3, the recording head 12 includes a head unit 15 that discharges hot melt ink and a tank unit 16 that stores hot melt ink supplied to the head unit 15. The hot melt ink used in the ink jet recording apparatus is a property that solidifies at room temperature, has a softening point of 40 to 140 ° C., a melting point of 50 to 150 ° C., and an ink viscosity of 3 to 50 cps when ejected from the ink. Is a general term for inks having a water content, preferably 30 to 90% wax, 5 to 70% resin, 0.1 to 10% colorant, and other additives (thickener and sea surface active agent). , Solubilizer, etc.).
[0015]
As shown in FIGS. 4 and 5, the head portion 15 has a nozzle plate 21 that faces the paper 20 and has a number of nozzles 21 a formed in the sub-scanning direction. The nozzle plate 21 is joined to the cavity plate 22, and the cavity plate 22 includes a large number of ink ejection grooves 22a and ink chamber grooves 22b formed corresponding to the respective nozzles 21a, and all the ink chamber grooves 22b. A connected ink supply groove 22c is formed.
[0016]
A diaphragm 23 is joined to the entire surface of the cavity plate 22. The diaphragm 23 is configured to form a nozzle chamber 27, an ink chamber 28, and an ink supply chamber 29 by closing the upper surfaces of the grooves 22 a to 22 c of the cavity plate 22. A large number of piezoelectric element members 24 supported by a base plate 25 are joined to the diaphragm 23, and each piezoelectric element member 24 is disposed above the ink chamber 28 via the diaphragm 23. Yes.
[0017]
The piezoelectric element member 24 is made of a material such as lead zirconate titanate (PZT) and applies a predetermined voltage (for example, 80 V) at a predetermined temperature (for example, 130 ° C.) when the recording head 12 is manufactured. Is polarized. Each of the piezoelectric element members 24 of this embodiment is provided with at least a pair of electrodes so that a driving voltage having the same polarity as the polarization direction is applied. In general, when an electric field identical to the polarization direction is applied, the piezoelectric element exhibits a characteristic of extending in the parallel direction of the electrode and contracting in the vertical direction. When a voltage is applied to the piezoelectric element member 24 through the electrodes, the piezoelectric element member 24 expands and contracts by an expansion / contraction amount corresponding to the applied drive voltage, and the diaphragm 23 is displaced up and down to thereby change the volume of the ink chamber 28. The ink in the ink chamber 28 is ejected in the direction of the paper 20 through the nozzle chamber 27 and the nozzle 21a.
[0018]
A front heater 26 (heating means) formed in a flat plate shape is joined to the base plate 25 supporting the piezoelectric element member 24 in a planar shape. As shown in FIG. 3, the front heater 26 is disposed from the base plate 25 to the ink supply path 16 a of the tank unit 16, and heats the hot melt ink in the piezoelectric element member 24 and the ink supply chamber 29 via the base plate 25. At the same time, the hot melt ink in the ink supply path 16a is heated.
[0019]
The ink supply path 16 a communicates with the ink storage chamber 16 b of the tank portion 16, and allows hot melt ink stored in the ink storage chamber 16 b to flow into the ink supply chamber 29. As shown in FIG. 6, a tank heater 31 (heating means) is affixed to the bottom wall of the ink storage chamber 16b, and the tank heater 31 heats the hot melt ink stored in the ink storage chamber 16b. To melt.
[0020]
As shown in FIG. 7, the front heater 26 and the tank heater 31 are composed of a flat base member 61 made of an insulating material such as alumina, and a heating material such as ruthenium oxide formed on one surface of the base member 61. An AC heater portion 62, a DC heater portion 63 made of a heat generating material such as ruthenium oxide formed on the other surface of the base member 61, and lead glass laminated on the upper surfaces of the AC heater portion 62 and the DC heater portion 63. And the like. And, electrode members 65 and 65 such as Ag-Pd formed on both surfaces of the base member 61 are connected to one end portions of the AC heater unit 62 and the DC heater unit 63, and the electrode members 65 and 65 are connected to these electrode members 65 and 65. AC power and DC power are supplied through the connected lead wires 66 and 66, respectively.
[0021]
The DC heaters 63 and 63 of the front heater 26 and the tank heater 31 are set to the minimum heat capacity necessary to maintain the molten state of the hot melt ink. As shown in FIG. Is connected to a DC power supply 74 (DC power supply means) provided in the housing. The DC heaters 63 and 63 are supplied with electric power from the DC power supply 74 during the period when the apparatus power supply is in the ON state (at the home position and at the scanning position).
[0022]
On the other hand, the AC heaters 62 and 62 of the front heater 26 and the tank heater 31 are set to a heat capacity sufficient to quickly heat the solid hot melt ink to the molten state, as shown in FIG. Further, it is connected to the socket 71 through a lead wire 66. The socket 71 is provided on the side wall 12a of the recording head 12 so as to face the side wall of the lower cover 1 on the home position side. The side wall of the lower cover 1 is provided with a plug 72 (AC power supply means) that is disposed opposite to the socket 71 and can be engaged with and disengaged from the socket 71. The plug 72 has the recording head 12 positioned at the home position. When this occurs, the socket 71 is engaged to be electrically connected. The plug 72 is connected to an AC power source 73 (AC power supply means) via an electromagnetic switch (not shown) and reinforced wiring 75 (AC power supply means) such as double insulation. Thus, the AC power source 73 supplies power to the AC heater portions 62 and 62 of the front heater 26 and the tank heater 31 only at the home position of the recording head 12 in which the socket 71 and the plug 72 are connected. It has become.
[0023]
The printing mechanism main body 11 including the front heater 26, the tank heater 31, the piezoelectric element member 24, and the like is controlled by a recording device control system 40 as shown in FIG. The recording apparatus control system 40 includes a CPU 42, ROM 43, RAM 45, timer 44, interface 49, mechanical control unit 47, heater control unit 53, and voltage control unit 54 connected via a bus 46.
[0024]
The ROM 43 stores various control programs such as a printing routine for printing the dot data in the output data storage area. The RAM 45 has an output data storage area for storing dot data in a matrix-like data table composed of main scanning direction addresses and sub-scanning direction addresses. The timer 44 outputs time data indicating the current time. The interface 49 is connected to an information processing apparatus such as a personal computer (not shown), and information such as image data from the information processing apparatus. Data is input to the recording apparatus control system 40.
[0025]
The mechanical control unit 47 is connected to a CR motor 55 that performs main scanning of the recording head 12 and a PF motor 56 that performs sub-scanning of the paper 20. The heater control unit 48 is connected to the front heater 26 and the tank heater 31 shown in FIG. 3 and obtains the heat generation temperature from the thermistors 50 and 50 provided in the heaters 26 and 31, respectively. The temperature is adjusted to a predetermined temperature. The voltage control unit 54 generates a drive voltage applied to the piezoelectric element member 24 of the recording head 12.
[0026]
The recording apparatus control system 40 having such a configuration melts hot melt ink by the DC heater portions 63 and 63 of the front heater 26 and the tank heater 31 during the printing operation in which the recording head 12 is located at the scanning position. While maintaining the state, by repeating the main scanning of the recording head 12 and the sub-scanning of the paper 20 by the operation of the motors 55 and 56, the dot data stored in the output data storage area of the RAM 45 is transferred to the paper 20 in units of one band. It is made to print with. In addition, when the recording head 12 is located at the home position, the hot melt ink is heated by the DC heater parts 63 and 63 and the AC heater parts 62 and 62 of both heaters 26 and 31 to promote melting. It has become.
[0027]
In the above configuration, the operation of the ink jet recording apparatus will be described.
As shown in FIG. 1, when the recording head 12 is located at the home position, the plug 72 on the lower cover 1 side engages with the socket 71 on the recording head 12 side to be electrically connected. Therefore, in this state, when the power of the recording apparatus is turned on, power is supplied to the AC heaters 62 and 62 of the heaters 26 and 31 via the reinforcing wiring 75, the plug 72, and the socket 71. Become. At the same time, power is also supplied from the AC power source 73 to the DC power source 74 via the reinforcing wiring 75 and converted to DC by the DC power source 74, and then this DC power is supplied to the heaters 26 and 31 via the lead wire 66. Are supplied to the direct current heaters 63 and 63.
[0028]
As a result, the AC heater unit 62 and the DC heater unit 63 provided in the front heater 26 generate heat, so that the hot melt ink existing in the head unit 15 in FIG. 3 is rapidly heated by a large amount of heat and is in a solid state. It will be made into a molten state. Further, when the AC heater unit 62 and the DC heater unit 63 provided in the tank heater 31 generate heat, the hot melt ink existing in the tank unit 16 of FIG. It will be in a molten state. Therefore, the hot melt ink is maintained in a molten state at a predetermined temperature by the AC heater unit 62 and the DC heater unit 63 until the apparatus startup is completed in a short time and the subsequent printing operation is performed. .
[0029]
Next, when the printing operation is started, as shown in FIG. 9, the mechanical control unit 52 performs main scanning of the recording head 12 via the CR motor 55 and also stores dot data stored in the output data storage area of the RAM 45. Therefore, the drive voltage is applied from the drive voltage generator 54 to the piezoelectric element member 24. As a result, as shown in FIGS. 3 and 4, the piezoelectric element member 24 expands and contracts by an expansion / contraction amount corresponding to the driving voltage, and the diaphragm 23 is displaced up and down to increase or decrease the volume of the ink chamber 28. 28 inks are ejected in the direction of the paper 20 through the nozzle chamber 27 and the nozzle 21a. When printing for one band is performed by the main scanning of the recording head 12, after the paper 20 is sub-scanned by the paper feed amount for one band by the PF motor 56, the next printing is started. Become. Thereafter, when printing on the paper 20 is completed, the paper 20 is discharged out of the apparatus from the conveyance path 7 through the paper discharge port 1a.
[0030]
At this time, as shown in FIG. 1, during the printing operation, when the recording head 12 is positioned at the scanning position by the main scanning, the socket 71 and the plug 72 are separated from each other. Is not supplied to the AC heater 62. Accordingly, the front heater 26 and the tank heater 31 are set to the minimum necessary for maintaining the molten state because only the power of the DC power source 74 is supplied to the DC heater portions 63 and 63 via the lead wires 66. The hot melt ink is heated by the heat capacity of the DC heaters 63 and 63, and the molten state of the hot melt ink is maintained. In such main scanning, the lead wire 66 connected to the recording head 12 becomes a factor that impedes the scanning stability of the recording head 12, but the lead wire 66 is more than the reinforcing wiring 75 for alternating current. Since it is extremely thin and flexible, the scanning stability of the recording head 12 is not reduced by the lead wire 66. Even when external power is included in the power of the AC power supply 73, the plug 72 and the socket 71 are separated from each other, so that the printing operation does not malfunction due to the external noise.
[0031]
In this embodiment, when the recording head 12 is located at the home position, the power of the AC power source 73 and the power of the DC power source 74 are supplied. However, the present invention is not limited to this. No, only the power of the AC power supply 73 may be supplied.
[0032]
【The invention's effect】
The invention according to claim 1 is an ink jet recording apparatus that performs printing by ejecting the hot melt ink while performing main scanning on a recording head including a heating unit that heats and melts the hot melt ink. An AC heater having a heat capacity sufficient to melt the hot melt ink and a DC heater having a minimum heat capacity necessary for maintaining the molten state of the hot melt ink are provided, and can be engaged with and disengaged from the AC heater. AC power supply means for engaging the AC heater when the recording head is located at the home position and supplying power to the AC heater, and at least when the recording head is not located at the home position DC power supply means for supplying power to the heater.
[0033]
Thus, when the recording head is at the home position, the hot melt ink is heated by the AC heater having a sufficient heat capacity to melt the hot melt ink, so that the hot melt ink is rapidly heated to be in a molten state. Therefore, the start-up of the apparatus can be completed in a short time. In the main scanning, the DC heater for heating the hot melt ink is set to the minimum heat capacity necessary for maintaining the molten state of the hot melt ink. The parts cost of the supply means can be reduced. Furthermore, during the main scanning, the AC heater and the AC power supply means are separated from each other, so that the scanning stability of the recording head is not reduced by, for example, the reinforcing wiring of the AC power supply means, and the AC power supply is not performed. There is an effect that the printing operation does not malfunction due to external noise included in the power of the means.
[0034]
According to a second aspect of the present invention, the DC power supply means according to the first aspect of the present invention is configured such that when the recording head is located at a home position, power is not supplied to the DC heater. Thereby, there is an effect that it is possible to further suppress the consumption of unnecessary power.
[0035]
According to a third aspect of the present invention, the heating means according to the first aspect has a flat base member made of an insulating material, and the AC heater and the DC heater are respectively formed on both surfaces of the base member. It is the composition which is. Thereby, since the AC heater and the DC heater are respectively formed on both surfaces of the base member, there is an effect that the heating means can be reduced in size.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an operation state of an ink jet recording apparatus.
FIG. 2 is a schematic configuration diagram of an ink jet recording apparatus.
FIG. 3 is an explanatory diagram showing an internal structure of a recording head.
4A and 4B are explanatory views showing an internal structure of a head portion of the recording head, where FIG. 4A is a front view and FIG. 4B is a side view.
FIG. 5 is an exploded perspective view of a head portion of a recording head.
6A and 6B are configuration diagrams of a tank heater, where FIG. 6A is a plan view, FIG. 6B is a front view, and FIG. 6C is a bottom view.
FIG. 7 is a longitudinal sectional view of main parts of a tank heater and a front heater.
8A and 8B are explanatory views showing the internal structure of the recording head, where FIG. 8A is a plan view and FIG. 8B is a front view.
FIG. 9 is a block diagram of a recording apparatus control system.
[Explanation of symbols]
11 Printing mechanism body 12 Recording head 15 Head unit 16 Tank unit 20 Paper 21 Nozzle plate 22 Cavity plate 23 Diaphragm 24 Piezoelectric element member 25 Base plate 26 Front heater 27 Nozzle chamber 28 Ink chamber 29 Ink supply chamber 31 Tank heater 53 Heater control unit 54 Voltage control unit 55 CR motor 56 PF motor 61 Base member 62 AC heater unit 63 DC heater unit 66 Lead wire 72 Plug 74 DC power supply 75 Strengthening wiring

Claims (3)

In an ink jet recording apparatus that performs printing by jetting the hot melt ink while main scanning a recording head provided with a heating means for heating and melting the hot melt ink.
The heating means includes an AC heater having a heat capacity sufficient to melt the hot melt ink, and a DC heater having a minimum heat capacity necessary to maintain the molten state of the hot melt ink.
AC power supply means that is detachable from the AC heater, engages with the AC heater when the recording head is located at a home position, and supplies power to the AC heater;
An ink jet recording apparatus comprising: a DC power supply means for supplying power to the DC heater at least when the recording head is not at a home position. 2. The ink jet recording apparatus according to claim 1, wherein the DC power supply means does not supply power to the DC heater when the recording head is located at a home position. The said heating means has a flat base member made of an insulating material, and the AC heater and the DC heater are respectively formed on both surfaces of the base member. Inkjet recording device.

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