JP2008093900A - Image formation apparatus and image formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a line head printer apparatus which can achieve stable high-speed printing by a simple apparatus configuration. <P>SOLUTION: In the image formation apparatus which forms an ink image at a desired image printing position on a recording paper P by simultaneously controlling a plurality of ink ejecting means 1 driven on demand, and deflecting electric field applying means 12 and 13 that electrically deflect a course of charged ink liquid droplets ejected from the ink ejecting means 1, detection of a charge amount of the ink liquid droplets and detection of non ejection are served by one detecting means 16. Not only control of the deflecting electric field applying means 12 and 13, but also detection of non ejection are carried out according to a charging state of the detected ink liquid droplets. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method such as a printer, a facsimile machine, a copier, and a printing machine, and in particular, recording is performed by intermittently discharging ink droplets onto a recording paper according to an image. The present invention relates to an on-demand ink jet printer that performs printing on paper.

  Conventionally, as an on-demand type ink jet printer that has been commercialized for office, home use, or business use, two methods, a thermal method and a piezoelectric method, have become mainstream.

  A thermal on-demand type ink jet head is an ink discharge nozzle provided for discharging a liquid, and a heat that communicates with the ink discharge nozzle and is a portion where thermal energy for discharging droplets acts on the liquid. The liquid discharge part which has the liquid flow path which makes an action part a part of structure, and the electrothermal conversion body as a means to generate | occur | produce a thermal energy are comprised.

  The electrothermal transducer includes a pair of electrodes, and a heating resistor layer connected to the electrodes and having a region (heat generating portion) that generates heat between the electrodes.

  A typical example showing the structure of such an ink jet head is shown in FIGS. 10 (a) and 10 (b).

  FIG. 10A is a front partial view of a typical inkjet head as viewed from the ink discharge nozzle side, and FIG. 10B is a cut surface when cut at a portion indicated by a one-dot chain line XY in FIG. FIG.

  The recording head 101 shown in FIG. 10 has a groove in which a predetermined number of grooves having a predetermined linear density and a predetermined width and depth are provided on the surface of the substrate 103 on which the electrothermal transducer 102 is provided. The ink discharge nozzle 105 and the liquid discharge portion 106 are formed by bonding so as to be covered with the attached plate 104.

  The recording head shown in FIG. 10 is shown as having a plurality of ink discharge nozzles 105.

  The liquid discharge unit 106 has an ink discharge nozzle 105 for discharging liquid at the end thereof, and heat energy generated by the electrothermal transducer 102 acts on the liquid to generate bubbles, which are caused by expansion and contraction of the volume. And a heat acting portion 107 that is a portion that causes a sudden state change.

  The heat acting part 107 is located above the heat generating part 108 of the electrothermal transducer 102, and has a heat acting surface 109 as a surface in contact with the liquid of the heat generating part 108 as its bottom surface.

  The heat generation unit 108 includes a lower layer 110 provided on the substrate 103, a heating resistance layer 111 provided on the lower layer 110, and an upper layer 112 provided on the heating resistance layer 111.

  On the surface of the heating resistor layer 111, electrodes 113 and 114 are provided for energizing the heating resistor layer 111 in order to generate heat.

  The electrode 113 is an electrode common to the heat generation part of each liquid discharge part, and the electrode 114 is a selection electrode for selecting the heat generation part of each liquid discharge part to generate heat, and the flow of the liquid discharge part It is provided along the road.

  The upper layer 112 is a liquid flow path between the heat generating resistor layer 111 and the liquid discharge unit 106 in order to chemically and physically protect the heat generating resistor layer 111 from the liquid (for example, ink) used in the heat generating unit 108. It has a protective function of the heating resistance layer 111 that isolates the liquid that satisfies the above condition and prevents a short circuit between the electrodes 113 and 114 through the liquid.

  In such a thermal method, it is basically easy to integrate heating elements, and a plurality of ink discharge nozzles can be arranged at a high density pitch.

  Next, FIGS. 11 (a) and 11 (b) show a typical example of the above-described piezoelectric on-demand type ink jet head with a cross-sectional view and a plan view omitted.

  This method is a method of ejecting ink droplets by pressurizing an ink chamber filled with ink with a piezoelectric element as an ink droplet ejecting means. The diaphragm 203 is disposed on a cavity 202 formed in the substrate 201. By joining, an ink chamber is formed.

  Further, a lower electrode 205, a piezoelectric element 204, and an upper electrode 206 are laminated on the vibration plate 203.

  In the cavity 202, an ink supply nozzle 208 and an ink supply chamber 208 communicating with the ink chamber are formed.

  A plurality of these elements are formed in a row on the substrate, and a voltage is selectively applied between the upper and lower electrodes 205 and 206 by an image signal (driving signal) S, whereby electrostriction occurs in the piezoelectric element 204. Occurs, and the diaphragm 203 bends rapidly.

  As a result, the volume of the ink chamber formed by the cavity 202 and the vibration plate 203 is reduced, and the ink droplet D is ejected from the ink ejection nozzle 207.

The feature of this method is that the ink droplet size can be controlled by a method of applying a voltage to the piezoelectric element 203 and the ink material can be selected relatively easily.
Japanese Patent Laid-Open No. 10-095150 JP-A-6-210856

  In recent years, in order to realize further high-speed printing of ink jet printers, a so-called line is used in which a printer head is lengthened and a plurality of printer heads are arranged in a direction perpendicular to the paper transport direction and printing is performed without moving the head. Many proposals for head printers have been made.

  For example, Japanese Patent Laid-Open No. 10-095150 proposes a line head printer that uses a full line type ink jet head that covers an A4 vertical size of 210 mm.

  In the proposed head, for example, by forming 5200 ink ejection nozzles at a density of 600 dpi (42.3 μm intervals), the printable width is about 220 mm.

  In recent years, the heads of inkjet printers are increasing in density to cope with higher image quality. For example, in a line head having a density of 1200 dpi (21 μm intervals), 10400 ink ejection nozzles are required. become.

  However, when a piezoelectric full-line ink jet head as described above is made at a high density pitch of 1200 dpi, for example, it is necessary to miniaturize and integrate each piezoelectric element.

  As a result, the amount of flexure of the diaphragm that is deflected by the deformation of the piezoelectric element is reduced, and the ink rejection volume in the ink chamber is also reduced accordingly. Therefore, it becomes difficult to eject ink from the ink ejection nozzle, and the inventors have studied. According to the existing piezoelectric material, it seems difficult to increase the density of 300 dpi or more.

  In addition, in the thermal method as described above, the integration of the heating elements is basically easy, so that it is possible to arrange a plurality of ink nozzles at a high density pitch, and many proposals have been made. Actually, processing accuracy such as the positions of the heating elements and the nozzles is required, and it is very difficult to increase the manufacturing yield.

  Here, in Japanese Patent Laid-Open No. 6-210856, an on-demand type printer that intermittently ejects ink droplets and prints a desired character or the like by intermittently driving ink ejection means in accordance with the character or the like to be printed. In the ink jet printer apparatus, a charging unit that charges the ink droplets ejected by the ink ejection unit and an electric field through which the ink droplets charged by the charging unit pass are formed. The above-described problem is solved by including a deflecting unit that changes the direction in which the ink droplets are ejected.

  The deflection means is driven by a voltage having a value corresponding to the magnitude of the charged ink droplet deflection, or a constant voltage applied for a time corresponding to the magnitude of the charged ink droplet deflection. It is supposed to be driven by.

  In this configuration, it is necessary to add the charging means, the deflecting means, etc., but the ink discharge nozzles can be arranged at a low density pitch, so that the processing accuracy is not increased and the piezoelectric method is also used. High-density image recording is possible without downsizing the piezoelectric element.

  However, the first problem with the above configuration is that the charged state of the ink droplet that determines the magnitude of the ink droplet deflection is not stable, so that the ink droplet is landed on the target print position by controlling the deflection means. It is difficult.

  The charged state of the ink droplets varies greatly depending on the environmental conditions such as the temperature and humidity of the printing place, the ink characteristics such as the difference between each color ink and the lot difference, and the ink flying in the deflecting means to which the same voltage is applied. When the charge amount of the droplet is large, the deflection amount is large, and when it is small, the deflection amount is small.

  For this reason, it is necessary to make the voltage application condition to the deflecting means appropriate depending on the charged state of the ink droplets, but it is very difficult to stabilize the deflected state of ink from the plurality of ink ejecting means to the German level.

  As a second problem, when ink droplets cannot be ejected from some nozzles, printing omission occurs over a wide range.

  In conventional serial type ink jet printers, even if ink cannot be ejected with a few nozzles, it is difficult to distinguish on the printed image on the paper, but in this method, the deflection width per nozzle is missing, so the printed image on the paper Results in missing prints parallel to the paper transport direction.

  The cause of the inability to eject ink droplets from the nozzle is considered to be an electrical failure of the heater or piezoelectric element and clogging of the nozzle due to paper dust or ink denatured material in the nozzle. Ink may be ejected by a known recovery means such as cleaning of the ink ejection section, but the former requires measures such as warning of failure because it cannot be recovered.

  SUMMARY An advantage of some aspects of the invention is that it provides a line head printer device with high printing stability capable of realizing further high-speed printing with a simple device configuration.

  The on-demand ink jet printer apparatus of the present invention simultaneously includes a plurality of ink ejection means driven on demand and a deflection electric field applying means for electrically deflecting the path of charged ink droplets ejected from the ink ejection means. In an image forming apparatus that controls and forms an ink image at a desired image printing position on a recording paper, an ink droplet charge state detection unit is disposed opposite to the ink discharge unit, and the charge of the detected ink droplet is detected. The aforementioned problem is solved by controlling the deflection electric field applying means according to the state.

  Furthermore, the above-described problem is solved by the fact that the charge state detection means also serves as an ink discharge detection means for detecting the ink discharge state from the ink discharge means.

  The on-demand ink jet printer apparatus of the present invention simultaneously includes a plurality of ink ejection means driven on demand and a deflection electric field applying means for electrically deflecting the path of charged ink droplets ejected from the ink ejection means. In an image forming apparatus that controls and forms an ink image at a desired image printing position on a recording paper, an ink droplet charge state detection unit is disposed opposite to the ink discharge unit, and the charge of the detected ink droplet is detected. By controlling the deflection electric field applying means according to the state, it is possible to apply an appropriate voltage to the deflection electric field applying means even when the charged state of the ink droplet is unstable. It is possible to provide a line head printer device with high printing stability that can realize high-speed printing.

  Further, since the charge state detection unit also serves as the ink discharge detection unit that detects the discharge state of the ink from the ink discharge unit, it is possible to easily determine a failure such as missing print.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the on-demand type ink jet printer apparatus according to this embodiment is a so-called line head in which the head unit 1 has a plurality of ink discharge nozzles 2a, 2b, 2c,. (Multi-head).

  FIG. 1 is a cross-sectional view of the main part of the head unit 1 cut in parallel to the direction in which the ink discharge nozzles 2 are arranged. FIG. 2 shows the main part of the head unit 1. A cross-sectional view for explaining the vicinity of one ink discharge nozzle 2 in more detail, and FIG. 3 is a cross-sectional view from the side.

  In the head portion 1, a pressure generating chamber 4 is formed by providing a concave portion by etching a silicon substrate having a thickness of about 150 μm at an arrangement pitch of the ink discharge nozzles 2 and covering the silicon substrate with the vibration plate 3.

  Further, an ink discharge nozzle 2 is formed on a surface opposite to the surface covered with the vibration plate 3, and an ink supply port 5 that supplies ink from the ink supply flow path 6 is connected to the pressure generation chamber 4.

  The vibration plate 3 is composed of a ceramic material that can be elastically deformed by the displacement of the piezoelectric vibrator 7 or a thin plate of metal material such as zirconia, silicon, etc. A piezoelectric vibrator type ink jet recording head can be configured by fixing the vibrator 7 corresponding to each pressure generating chamber 4 and applying a signal from the drive power supply 10 corresponding to the print signal.

  Thus, the ink droplets D ejected on demand from the ink ejection nozzle 2 are deflected electrodes 12 and 13 which are part of a deflection electric field applying means to which a voltage is applied from the deflection electric field forming power source 14 in synchronization with the ejection timing. The flying path is deflected by passing through the deflection electric field in a direction substantially perpendicular to the ejection direction of the ink droplet D, and landed on the desired image printing positions (D1 to D5) on the recording paper P. .

  In this deflection electric field applying means, deflection electrodes 12 and 13 are arranged on an insulating film 15 formed in the vicinity of the ink discharge nozzle 2 on the silicon substrate on which each ink discharge nozzle 2 is formed so as to sandwich the ink flight path. These are alternately provided along the arrangement pitch of the ink discharge nozzles 2 in the direction perpendicular to the conveyance direction p of the recording paper P.

  Further, the ink ejection state from the ink ejection nozzle 2 is detected in such a manner that the conveyance path of the recording paper P is sandwiched below the plurality of ink ejection nozzles 2a, 2b, 2c... Covering the entire width of the recording paper P. At the same time, a charge state detection means 16 for detecting the charge amount of the ink droplet is provided.

  The charge state detection means 16 is a flat plate made of a material such as Al, Cu, SUS or the like having high conductivity such as Au, Pt, Cu on the surface, and in this embodiment, an Au electrode is formed on the surface of the Al substrate by sputtering. It is a thing.

  As the shape of this charged state detection means 16, considering the absorption of ink, etc., a porous structure having pores smaller in diameter than the ink droplet size, for example, a structure such as a SUS mesh with Au deposited on the surface You can also.

  Next, the charge state detection method of the present invention will be described.

  The ink droplet D ejected from the ink ejection nozzle 2 when not passing is charged by the separation process from the ink base and the friction process with the air layer in flight, etc., facing the ink ejection nozzle 2 with a distance of several mm. Landing on the surface of the charged state detection means 16 provided.

  The landed ink droplet D releases a charge to the Au electrode on the surface of the charge state detection means 16, and this charge flows into the charge amount detection circuit 17, and the charge state detection process is performed by a conventionally known charge amount detection method such as a capacitor circuit. Is done.

  Here, in order to increase the detection accuracy, it is necessary to increase the amount of charge (current) to be detected.

  In the present embodiment, highly accurate detection can be performed in a short time by discharging ink from all nozzles simultaneously.

  Here, depending on the charge state of the ink, it is not necessary to eject from all the nozzles, and high accuracy can also be achieved by performing ink ejection from odd-numbered rows or even-numbered rows only, at regular intervals, or from a plurality of appropriately selected nozzles all at once. Detection is possible.

  In this way, the detected charge (current) amount is converted into a voltage value, subjected to processing such as amplification and filtering, then AD conversion, sent to a signal processing control circuit 35 as shown in FIG. The applied voltage between the deflection electrodes 12 and 13 is determined.

  Also, in the ink discharge state detection process, ink discharge from each ink discharge nozzle 2 is continuously performed a plurality of times for each individual nozzle, and the detected charge (current) amount is converted into a voltage value, and then amplified and filtered. After performing the above-described processing, it is AD-converted, sent to the signal processing control circuit 35, and then subjected to arithmetic processing. Based on the detected value, the presence or absence of ink ejection from each nozzle is determined, and processing such as image correction and warning is performed.

  It is also possible to calculate the charge state by totaling the amount of charge detected in this ink discharge state detection process.

  FIG. 5 shows ink droplets ejected four times in the order of 2a, 2b, and 2c in the non-ejection state of the ink ejection nozzles 2a, 2b, and 2c of FIG. 1 in the ink ejection state detection process. And the output signal integrated after being detected and amplified by the charge amount detection circuit 17 due to the discharge of charges on the charge state detection means 16, and four inks from the nozzles 2a and 2c. The output signal gradually increases with the discharge, but no output is output from the nozzle 2b in the non-discharge state.

  Here, when an output signal equal to or greater than the threshold value X is not detected, it is determined that ejection from the nozzle is not completed.

  In the present embodiment, the charge state detection process and the ink discharge state detection process are performed without applying the deflection electrode voltage to the deflection electrodes 13 and 14, but each detection process can be performed with the applied state.

  Next, the flight path of the ink droplet D is deflected with an appropriate applied voltage between the deflection electrodes 12 and 13 determined by the charge state detection of the ink droplet by the method described above, and a desired on the recording paper P is obtained. An electric circuit configuration to the head unit 1 for landing the ink droplet D at the image printing position to be performed will be described with reference to FIG.

  In FIG. 6, the head unit 1 is applied to the lower electrode 8 and the upper electrode 9 of the piezoelectric vibrator 7 based on a print trigger supplied from the input terminal 20, and a piezoelectric element enable signal for controlling the ink discharge timing and A timing signal generation circuit 21 that generates and outputs a latch signal for converting serially supplied print data into parallel data, and a deflection electrode control signal from the timing signal generation circuit 21 is converted into a voltage to convert each deflection. And a voltage generation circuit 22 to be applied between the electrodes 12 and 13.

  The serial data is formed in accordance with the print information. The serial / parallel conversion circuit 24 converts the print data 23 supplied by serial transmission into parallel print data and outputs the parallel print data. A piezoelectric element controller 25 that forms and outputs a piezoelectric element control signal for controlling each piezoelectric vibrator 7 based on the piezoelectric element enable signal and the print data from the serial / parallel conversion circuit 24, and a piezoelectric element controller A piezoelectric element driver 26 that drives the piezoelectric vibrator 7 by applying a voltage to the lower electrode 8 and the upper electrode 9 of the piezoelectric vibrator 7 based on a piezoelectric element control signal from 25.

  The on-demand type ink jet printer apparatus includes the head unit 1 shown in FIG. 7 and a memory (line buffer memory or frame memory) that temporarily stores print data supplied from the outside via the input terminal 30 as necessary. 31) and γ correction of the print data, color correction when the print data is color, charge state of ink droplets detected by the charge amount detection circuit 17, and variations in print capability due to non-ejection nozzles Based on the correction circuit 32 that performs correction and the like, the driver 33 that drives the head unit 1, the control system 34 that controls the motor drive that transports the recording paper P, and the print data supplied from the outside, the head The control unit 35 includes a control unit 35 that controls a unit 1, a memory 31, a correction circuit 32, a driver 33, and a control system 34.

  Next, the operation of the on-demand type ink jet printer apparatus according to this embodiment having the above-described configuration will be described.

  First, when print data is transferred from a personal computer or the like to the on-demand type ink jet printer apparatus of the present invention, it is serially transmitted as shown in FIG. 8A, via the input terminal 30 shown in FIG. To the control circuit 35.

  When the serial print data is supplied, the control circuit 35 supplies the print data to the head unit 1 in the printing order, and drives a motor or the like that transports the recording paper P based on the serial print data. The drive data for this is supplied to the control system 34.

  In the case of the on-demand type ink jet printer apparatus according to the present embodiment, the shape of each ink discharge nozzle 2, the deformability of each piezoelectric vibrator 7, the charge amount of ink detected by the charge amount detection circuit 17, and between each deflection electrode There is a variation in the printing capability of each head due to the printing capability generated by the above, and the serial print data may need to be corrected.

  For this reason, the correction circuit 32 includes data (ink ejection nozzle number, temperature / humidity, input signal, etc.) for correcting variations in the printing capability of the heads and data (γ for correcting the serial print data). Correction, color correction, etc.) are stored in advance in the ROM, etc., and the control circuit 35 corrects the serial print data based on the data, and the serial print data subjected to the correction is printed in the printing order. Aligned and supplied to the head unit 1.

  In addition, since the print order differs depending on the configuration of the head unit 1 and the print unit, and also has a relationship with the print data input order, the control circuit 35 temporarily stores the print data in the memory 31 as necessary. Writing and reading are performed to supply print data to the head unit 1.

  When the drive data is supplied from the control circuit 35, the driver 33 supplies the drive data to the head unit 1 as a print trigger.

  Next, in FIG. 6, the serial print data from the control circuit 35 is supplied to the serial / parallel conversion circuit 24 via the input terminal 23, and the drive data from the driver 33 is supplied via the input terminal 20. It is supplied to the timing signal forming circuit 21.

  The timing signal forming circuit 21 forms a latch signal shown in FIG. 8B, a piezoelectric element enable signal shown in FIG. 8D, and a deflection electrode control signal shown in FIG. 8E based on the drive data. These are supplied to the serial / parallel conversion circuit 24, the piezoelectric element controller 25, and the voltage generation circuit 22, respectively.

  The serial / parallel conversion circuit 24 latches the serial print data supplied via the input terminal 23 at the timing of the latch signal shown in FIG. These are supplied to the piezoelectric element controller 25 (FIG. 8C).

  The piezoelectric element controller 25 forms a piezoelectric element control signal based on the parallel print data and the piezoelectric element enable signal shown in FIG. 8D supplied from the timing signal forming circuit 21 and outputs the piezoelectric element control signal to each piezoelectric element. This is supplied to the element driver 26. The piezoelectric element driver 26 amplifies the piezoelectric element control signal and supplies it between the lower electrode 8 and the upper electrode 9 of the piezoelectric vibrator 7.

  Further, the voltage generation circuit 22 is determined by the charge state detection process described above based on the deflection electrode control signal shown in FIG. 8 (e) synchronized with the piezoelectric element enable signal (d). A sawtooth waveform voltage having a period corresponding to the pitch between nozzles is used as a deflection electrode voltage, and this is applied between the deflection electrodes 12 and 13, respectively.

  In this embodiment, the deflection electrode control determined by the charge state detection process is performed by waveform control. However, time control, voltage amount control, or a combination thereof may be performed.

  As a result, the ink droplet D ejected from the nozzle 2 is distributed to the desired positions D1, D2,..., Dn on the recording paper P according to the ejection timing when passing between the deflection electrodes 12 and 13. It is done.

  This printing process will be described in more detail with reference to FIG.

  9A is a waveform diagram of the deflection electrode voltage applied between the deflection electrodes 12 and 13, and FIG. 9B is a flight path at each timing of the ink droplet D flying from the nozzle 2 by the deflection electrode voltage. FIG. 9C is a schematic diagram of the ink droplet D at each timing printed on the recording paper P that is continuously transported in the direction perpendicular to the head arrangement direction after flying.

  Here, consecutive numbers represent relative times, and when a voltage in the ± direction is applied with a sawtooth waveform as shown in FIG. 9A, each ink droplet from the nozzle 2 as shown in FIG. 9B. It flies sequentially and is printed sequentially as shown in FIG.

  The frequency of this deflection electrode voltage is an integral multiple of the frequency of the piezoelectric element control signal. Here, by setting the frequency to 5 times, for example, five ink droplets are ejected within one cycle of the deflection electrode voltage. When these five ink droplets land on the recording paper P, five dots are arranged, and printing is performed for a distance W corresponding to the pitch between adjacent nozzles.

  At the same time, the recording paper P is transported in a direction perpendicular to the direction in which the head is disposed. In this embodiment, the dot diameter w1 of the printed ink droplet (assumed to be circular when the ink soaks into the recording paper). In this case, the distance corresponding to W / 5 is moved by the time corresponding to one period of the voltage waveform, that is, the recording paper is conveyed at a speed of w1 · f (f: frequency of the deflection electrode voltage). As a result, it is possible to print an ink dot array with no disturbance at an equal pitch as shown in FIG.

  The ink dot shape and size on the recording paper in FIG. 9C described above vary depending on the ink physical properties (viscosity, surface tension, etc.) and the material physical properties of the recording paper P. Therefore, the number of ink ejections in one cycle is appropriate. By selecting this, white streaks or the like in the solid image can be prevented.

  In this embodiment, a thermal ink jet recording head is constructed by disposing a Joule heat generating element 41 in each pressure generating chamber 40 as shown in FIG. 43 can be used for printing, and a conventionally known on-demand type droplet discharge means such as a piezoelectric method such as a piston mode or a shear mode, an electrostatic method, or a magnetic method can also be applied.

  In any ink discharge means, the pressure generation chamber is pressurized in response to the drive signal to discharge the ink droplet D from the ink discharge nozzle, and then the ink flight path is deflected by the method of the present invention.

  Furthermore, it is needless to say that the present technology can be applied to conventionally known technologies other than ink jet such as toner jet and wax jet.

  In addition, it is also effective to apply this embodiment after providing charging means for charging the ink droplets before passing through the deflection electrode so that the ink droplets D can be more stably charged. is there.

  In the description of the above-described embodiment, the head portion 1 is a side shooter type, but it is needless to say that it may be a so-called edge shooter type.

  Furthermore, a full-color image can be printed by arranging a plurality of line heads arranged in parallel perpendicularly to the conveyance direction of the recording paper and supplying ink of at least yellow, magenta, cyan, black, etc. to each. Of course.

FIG. 3 is a cross-sectional view of the main part of the head unit 1 of the ink jet printer apparatus according to the embodiment of the present invention cut in parallel to the direction in which the ink discharge nozzles are arranged. FIG. 3 is a cross-sectional view for explaining the main part of the head unit 1 of the ink jet printer apparatus according to the embodiment of the present invention in more detail in the vicinity of one ink discharge nozzle. FIG. 3 is a cross-sectional view from the side for explaining the main part of the head unit 1 of the ink jet printer apparatus in the embodiment of the present invention in more detail in the vicinity of one ink discharge nozzle. It is sectional drawing for demonstrating in detail the principal part of the head part 1 of the inkjet printer apparatus in the other Example of this invention about one ink discharge nozzle vicinity. It is a figure which shows the relationship between the ink discharge amount and the output signal from a charge amount detection circuit. 1 is an overall block diagram of an inkjet printer apparatus in an embodiment of the present invention. 1 is a block diagram of a signal processing control system of an ink jet printer apparatus according to an embodiment of the present invention. It is a time chart explaining operation | movement of the inkjet printer apparatus in the Example of this invention. FIG. 4 is a schematic diagram showing a waveform of a voltage applied to the deflection electrode of the head unit 1 of the ink jet printer apparatus according to the embodiment of the present invention, a flight path of ink droplets, and a printing state at this time. It is sectional drawing of the head part of the conventional thermal type on-demand inkjet printer apparatus. It is sectional drawing and a plane omission figure of the head part of the conventional piezoelectric type on-demand inkjet printer device.

Explanation of symbols

1 Head 2 Ink discharge nozzle (nozzle)
DESCRIPTION OF SYMBOLS 3 Diaphragm 4 Pressure generating chamber 5 Ink supply port 6 Ink supply flow path 7 Piezoelectric vibrator 8 Lower electrode 9 Upper electrode 10 Drive power supply 12, 13 Deflection electrode 14 Deflection electric field formation power supply 15 Insulating film 16 Charge state detection means and ink discharge Detection means 17 Charge amount detection circuit 20 Input terminal 21 Timing signal generation circuit 22 Voltage generation circuit 23 Print data 24 Serial / parallel conversion circuit 25 Piezoelectric element controller 26 Piezoelectric element driver 40 Pressure generation chamber 41 Joule heat generation element 42, 43 Deflection electrode
D Ink droplet P Recording paper
Threshold for judging discharge from X nozzle

Claims (3)

  A plurality of ink ejecting means driven on demand and a deflection electric field applying means for electrically deflecting the path of the charged ink droplets ejected from the ink ejecting means are simultaneously controlled so that an image printing position on the recording paper is obtained. In an image forming apparatus for forming an ink image, an ink droplet charge state detection unit is disposed opposite to the ink discharge unit, and the deflection electric field applying unit is controlled according to the detected charge state of the ink droplet. An image forming apparatus.   The image forming apparatus according to claim 1, wherein the charge state detection unit also serves as an ink discharge detection unit that detects a discharge state of ink from the ink discharge unit.   The image forming apparatus according to claim 1, wherein ink discharge to the charge state detection unit is performed simultaneously from a plurality of ink discharge units.

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