JPH02196661A - Ink recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ink recording device, and particularly to an ink recording device, in which ink is supplied at a constant pressure to an ink jet head, and a vibrator applies pressure vibrations to the pressurized ink in the ink jet head. Then, the ink particles are ejected from the ink ejection head by this pressure vibration, and the ejected ink particles are charged in accordance with the image signal, and the charged ink particles are deflected by a deflection electric field to achieve a deflection of more than a predetermined level. One of the ink particles having a deflection and the ink particles having a deflection below a predetermined level is captured by the gutter, and the other is caused to collide with the recording paper. Regarding charge deflection type ink recording device -
6゜ [Prior Art] This is a typical ink recording device of this type.

A charging electrode is disposed between the ink jetting nozzle and the deflection electrode, and a charging voltage is applied to the charging electrode at the timing when the ink is turned into particles from the ink jetting nozzle.

Due to the electric field between the charged electrode and the ink in the head, charges of opposite polarity to the charged electrode are concentrated at the leading edge of the ink protruding from the ink ejection nozzle, and when the protruding ink separates into particles, the ink particles Carrying only charges of opposite polarity (charge). The charged ink particles are deflected by a deflection electric field while passing between the deflection electrodes. For example, uncharged or low-level charged ink particles collide with the gutter and are collected in the ink tank, while ink particles charged to a predetermined level or higher pass outside the gutter and collide with the recording paper (recording). There are also ink recording devices that use light irradiation to separate ink particles from the head using irradiation. generates bubbles in the irradiated area. Since the ink is pressurized in the area where the bubble occurs, the ink protrudes from the head and advances to the recording paper.

[Problem to be solved by the invention]

In the charge deflection type ink recording apparatus described above, the charge electrode is located in the space between the ink ejection nozzle and the deflection electrode, so when ink ejection starts or ends.

Because the ink ejection speed is low, it collides with the charging electrode and the charge ff
Contaminates the i-electrode. Furthermore, the charging electrode becomes dirty due to ink splashes caused by the ink jetting. When a charging electrode gets wet with ink, the charging characteristics of the charging electrode change and the amount of charge on the ink particles becomes unstable.In the case of multi-nozzle recording, in which many horizontal dots are recorded virtually simultaneously, adjacent charges may become unstable. The ink short-circuits the electrodes, making it impossible to achieve the desired charge. In addition, in multi-nozzle recording, a charged electrode is placed in the space between the ink ejecting nozzle and the deflection electrode independently of the ink ejecting nozzle, and ink particles ejected from one ink ejecting nozzle are transferred to one charged electrode (cylindrical). In addition, adjacent charging electrodes must be insulated, making it difficult to shorten the arrangement pitch of charging electrodes and making it impossible to arrange ink jet nozzles in high density. .

In the above-mentioned light irradiation type ink recording apparatus, a human-powered laser (N
2 lasers) are required. This output is about 2,000 times the exposure power of a semiconductor laser used to expose a photoreceptor in electrophotographic recording, for example, and there is no hope that it will become widespread.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink recording device rlX that can perform high-resolution and high-speed recording with low-power light irradiation.

[Means to solve the problem]

The ink recording device of the present invention includes a light-transmitting substrate (1) having a conductive surface (2), and a photoconductor (3) bonded to the surface (2).
, 4), a member (8) forming an ink ejection path (8bi) along the surface of the photoconductor (3, 4), an ink ejection path (8bi);
bi), an electric field ti(
7), an ink recording head (10) including an ink flow path (54) for supplying ink to the ink ejection path (8bi), and a vibrator (35) that applies pressure vibrations to the ink in the ink flow path (54); ; An ink supply means (SO) that supplies ink at a constant pressure to the ink flow path (54) ; A voltage is applied between the surface (2) of the base (1) of the ink recording head (]0) and the electrode (7); Charging voltage power supply circuit (51); Light irradiation means (30) for irradiating image-compatible light to the optical conductors (3, 4) through the transparent substrate (1); In front of the ink jetting path (8bi); Deflection electrodes (36, 37) that face each other with the flight trajectory of ink particles ejected from the ink jet path (8bi) in between; a deflection voltage power supply circuit (53) that applies a deflection voltage between the deflection electrodes (36, 37); ; Ink is ejected from the ink ejection path (8bi) and the deflection electrode (313, 3
7) The deflection electrodes (36, 37)
) is provided with a gutter (3g) that captures deflection caused by the electric field between the two sides, which is either greater than or equal to a predetermined value or less than a predetermined value. In addition,
Symbols in parentheses indicate corresponding elements in the embodiments shown in the drawings and described below.

[Effect]

According to this, the light irradiation means (30) is connected to the photoconductor (3, 4).
), the photoconductor generates carriers (electrons and holes) in response to the light, and among these carriers, the potential polarity (positive) of the substrate (1) surface (2) is opposite to that of the substrate (1) and the surface (2). (minus) carriers (electrons) are transferred to the surface of the substrate (1) (
2), carriers (holes) having the same potential polarity as the potential polarity of the substrate (1) and surface (2) are drawn to the ink ejection path (8bi).
The ink in the ink ejection path is charged. When there is no light irradiation, this charge does not substantially occur, so the light irradiation means (30) emits light corresponding to an image onto the photoconductor (
3, 4).

An image-corresponding charge is formed on the ink in the ink jet path (8bi).

The ink in the ink jetting path (8bi) is discharged from the ink jetting path (8bi) at the high peak point of the pressure vibration given by the vibrator (35).
The charged ink particles are deflected by the deflection electric field between the deflection electrodes, while the uncharged ink particles travel straight.

For example, by using a laser exposure scanning device as the light irradiation means (30) and forming an ink ejection path along the scanning direction, ink corresponding to one scanning line is ejected in one ejection, and one line recording is performed. It is possible to do so.

Therefore, according to the ink recording device of the present invention, the charged electrode between the ink recording head and the deflection electrode is omitted, and ink recording can be performed using low power light irradiation similar to electrophotographic laser exposure scanning. This enables high-resolution and high-speed recording with low-power light irradiation.

Other objects and features of the present invention will become clear from the following description of an embodiment with reference to one drawing.6 [Embodiment] FIG. 1 shows an outline of the configuration of an embodiment of the present invention.

Ink in the ink tank 40 is sucked by a pump 42, pressurized, and supplied to an accumulator 43. In the accumulator 43, the pump 42 suctions.

Pressure fluctuations due to discharge are absorbed. Ink at a constant pressure is supplied to the ink recording head 1° through the electromagnetic switching valve 44. In the head 1o, the ink is charged to a positive potential by a laser beam irradiated by the laser scanning device 30 (light is emitted when the image signal is recorded; no light is emitted when the image signal is not recorded). When there is no light irradiation, there is virtually no charge.

Furthermore, constant frequency pressure fluctuations are applied to the ink by constant frequency excitation of the vibrator. As a result, ink particles corresponding to one main scanning line are simultaneously ejected from the ink ejection ports of the ink ejection head 10. The charged ink particles are connected to deflection electrodes 36 and 3.
The uncharged ink particles that are deflected by the deflection electric field between the recording paper 11 and the recording paper 11 supported by the platen 39 (recording) collide with the gutter 38 for capturing non-printing ink particles.

Ink in the gutter 38 is sucked by a pump 45 and returned to the ink tank 40. Ink from the ink cartridge 41 is supplied to the ink tank 4o so that the ink level in the ink tank 4° is constant.

When ink ejection is stopped, first the pump 42 is deenergized and the 1
Next, the solenoid of the electromagnetic switching valve 8 is deenergized, and then the pump 45 is deenergized. The electromagnetic switching valve 44 disconnects the accumulator 43 and the head 10 and communicates the accumulator 43 and the ink tank 40 by deenergizing the solenoid.

A light-receiving slit 9a for receiving laser light is provided on the top surface of the helad base 9 of the ink recording head 10, and a laser exposure and scanning device 3o irradiates the light-receiving slit 9a with the laser light. An ejection port for ejecting ink is opened on the front surface of the ink recording head 1o along the longitudinal axis of the head 1o.
There is a gutter 38 behind 7.

The laser exposure scanning device 30 is a well-known device used in so-called laser printers, and has an oscillation wave of 1780±1.
Light emitted by a light source 15 incorporating a 0 n+m laser diode passes through a first cylindrical lens 16 and is then reflected by a first mirror 17 .

Next, through the spherical lens 18, the rotating polygon mirror 19
is irradiated. The rotating polygon *19 is rotated at a constant speed by a motor 20 and reflects the irradiated light.

By rotating the polygon mirror 19, the -
As the angle with respect to the irradiation light increases sequentially, in the illustrated example,
The mirror surface for the irradiated light is updated every 360 degrees/6 rotations, and the reflected light from the polygon mirror 19 is repeatedly swung (line scanning; main scanning) The light reflected by the 0-rotation polygon mirror 19 is transferred to the second mirror. Reflected by the SM, the second cylindrical lens 21
The light passes through the light receiving slit 9a of the recording head 10. During line scanning, a recording control device (not shown) turns on/off the laser diode of the light source 15 in response to an image signal (a signal indicating recording/non-recording of line content dots) to determine whether light is irradiated or not. In order to obtain an optical scanning line synchronization signal representing the line scanning break (switching of the reflecting surface and switching of the second line), a mirror 22 is placed outside the line scanning section, and the light reflected by this mirror 22 is The detected light is detected by the photosensor 23, and this detection signal (exposure scan synchronization signal) is given to the recording control device.

In the recording apparatus, the entire surface of the paper is scanned for recording by one or more main scans (line scans) and sub-scans (paper feeds) in which the platen 39 is fed at a constant speed (if constant scan drive is energized).

FIG. 2 shows an enlarged cross-sectional view of the ink ejecting section of the ink recording head 10, FIG. To explain the structure of the ink recording head 1o with reference to the figure, a helad base 9 is adhered to the upper half 31 of the ink recording head 1o, and a Nesa glass 1 is fixed to this head base 9 by adhesive. . Nesa glass 1 has a transparent conductive layer 2 on its surface.

On the conductive layer 2, there is a charge generation layer (both of which are organic photoconductors).
CGL) 3 and a charge transfer layer (CTL) 4 are bonded together, and the surface of the charge transfer layer 4 is coated with a protective layer (1'L) 5. The conductive layer 2 of the Nesa glass 1 is the power supply circuit 51
is connected to the positive output terminal of the

Electric charge is generated in the lower half 6 of the ink recording head 10! (CG
L)3 and charge transport layer (C:TL)1. An electrode (conductive layer) 7 is bonded to one opposing portion, and this 1! On the pole 7, a large number of comb-like nozzle partition walls 8ai made of synthetic resin
are formed at a pitch of 100 μ along the laser scanning direction.

FIG. 3b shows an enlarged appearance of the ink ejection partition wall 8ai. This nozzle partition wall 8ai has an insulating anti-etching coating (resist layer) applied to the entire surface of the lower half body 6 and the electrode 7, and the electric t! A synthetic resin sheet (8) is bonded to the surface of i 7, and the sheet (8) is etched to a thickness of 100 μm.
It is formed by etching in pitch until the electrode 7 is exposed. Nozzle partition walls 8ai face the photoconductors (3, 4), and together with the photoconductors, define ink ejection paths 8bi between adjacent nozzle partition walls (8ai). The pressurized ink supplied to the ink flow path 54 of the ink recording head 10 reaches this ink ejection path 8bi and is ejected from there.

The head base 9 has a light receiving slit 9a for irradiating a laser beam onto the organic photoconductor (3°4) directly above the ink jetting path 8bi through the Nesa glass l. The diameter of the ink jetting path 8bi is 100μ;
The array length of bi (length in the main scanning direction) is 210+wn+.

The laser beam projected by the multifaceted JII 19 is irradiated onto the Nesa glass 1, passes through it, and forms the charge generation layer (CG).
L) 3, and this irradiation generates photocarriers (holes and electrons) in the charge generation layer 3. Since the conductive layer 2 has a positive potential, the electrons generated in the charge generation layer 3 have a conductive J'
It neutralizes with the hole of l12 and disappears. On the other hand, charge generation layer 3
The holes generated move in the charge transfer layer (CTL) 4, pass through the protective film (PL) 5, and are injected into the ink in the ink ejection path 8bi.

At this time, the CGM in the charge generation layer 3, the donor I in the charge transfer layer 4, the donor I1 in the ink, and the donor I1. The respective ionization potential energies (rp) of CGM-u′, donor (I) I p
, Donor (IT) IP.

CGV IP > Donor (T) IP > Donor (II) r
Each material is selected so that p.

Figures 4a, 4b, and 4c show the molecular structural formulas and values of ionization potential energy IF of CGM, donor (I), and donor (■) selected as described above.

The charge generation layer 3 is made by dispersing CGM and a binder resin, and the charge transfer layer 4 is made by dispersing the donor (1) and a binder resin in a suitable solvent, and the dry film thickness is made to be <0.3μ.
The charge transfer layer 4 is formed by spray coating to a thickness of 1 μm.

Since CGM is soluble in the ink solvent, the charge transfer layer 4 has a high resistance to X! One layer is required as an undercoat layer to uniformly coat the thin (0.3μ) protective film (PL) 5.

The material of the protective layer 5 is polyamide resin so as not to block or trap holes.

The ink solvent needs to have high resistance in order to prevent holes from spreading in the lateral direction, and is a petroleum-based solvent that is commonly used as a wet 15'l imager for m-photography. Isovar G, H, and L were used. Dye Direct Black #19 is suitable as a coloring material, with a content of 10 (
In addition, the ink also contains donor (II).
is dispersed at 10 [nt%].

The potential of the conductive layer 2 of the Nesa glass 1 is +1. Qkv, the potential of electrode 7 is 0.0kv (that is, it is grounded), and the distance between 2 and 7 is 0.1wm, so
Due to this potential difference, 1.0/10' (V/■]
electric field is applied. By light irradiation, i! The number of holes generated is about 1/10? (Coulomb/C■2).

100μ x 100μ (equivalent to the area of 1 pixel) is 1/1
0" [coulomb], which is a radius of 62 μ (100
The total charge amount of the ink droplet is μcubic=4/3πr1, so r=62μ).

The mobility μ of holes in an oil-based ink containing 10 [nt%] of donors is 1/10 @ (cm2/VSI, so the velocity V of holes in the ink is ■ = μE = 1/10 "X 10' = 1/10
' (cII/sl. Time for one line to be scanned by the laser exposure scanning device 30, 1 (m 5ec
), the distance X that this hole moves between is x = v t = 1/10" X l/10" = 1
/10' (am) = 1/10' (mm), that is, from the charge transfer layer 4 to the ink ejection path 8
The holes injected into the ink of ai are connected to the lower electrode 7.
Finish scanning one line before reaching .

After one line of scanning is completed and before the first scan begins, an excitation voltage is applied to the vibrator 35 made of a bimorph piezo element of the recording head IO.

The vibrator 35 opens the ink flow path 54 when a pulse voltage is applied.
It swells (curves) to the side and pressurizes the ink in the ink flow path 54. This pressure propagates to the ink in the ink ejection path 8ai, and the ink is ejected. That is, ink corresponding to l main scanning lines is simultaneously ejected from each ink ejection path (8ai).

Ink to be ejected at this time (-line, 21010.1
= 2100 pieces) includes both charged ink in the laser irradiated area and uncharged ink in the non-laser irradiated area.

The voltage applied to the vibrator 35 is a constant-period pulse that turns on and off every time one main scanning line finishes scanning.
When a voltage of a certain polarity is applied, the vibrator 35 bends back to bulge toward the ink flow path 54 and pressurizes the ink.
When the voltage disappears or a voltage of the opposite polarity is applied, the ink flow path 54 is bent outward (reversely warped) and the ink pressure in the ink flow path 54 is lowered. FIG. 5 shows the relationship between the repetition of laser exposure scanning and the ink pressure in the ink jetting path 8ai due to the excitation of the vibration T-35.

The ink jetted from the ink jetting path 8at is -1, (i
(It passes between the deflection electrode 36 to which the kv1 potential is applied and the grounded deflection electrode 37. The gap between the deflection electrodes ff13G and 37 is 8 (l), so between them.

There is an electric field of E = 2X to' (V/+).

The force F that an ink droplet (1 pixel: l dot) ejected from one of the ink ejection paths 8ai receives between the deflection electrodes Fi3G-37 is as follows: F = q E = 1/10"X2X10' = 2
/10' (N).

When the flying speed of the charged ink particles is set to 5 [toward ■], the charged ink particles pass between the deflection electrodes 36° and 37 having a length of 10 (ms) in the ink flight direction at t = 2/10' (see).

The force F that the charged ink particles experience between the deflection electrodes 36,37
= 2/10'' (N), the acceleration α generated in the deflection direction is a = F/m = 2/10 (Nl'/l/10' (
kg) = 2xlo' (Peng/5ecl), and while flying between the deflection electrodes 36.37, Y =
1/2・αt' = 1/2・2 X 103・(2/
10')2=4/103(ml 103(+*) will be deflected upward.Furthermore, the deflection electrode 36°37
The distance from passing through the gap to the recording paper 11 is 10 [■], and since the charged ink particles fly between this gap, a=2/
10" (5ee) of time and the deflection electrode plate 36.
The speed vy of moving in the Y-axis upward direction (deflection direction) after passing through 37 is V y = (X t = 2XIO'4/10'' = 4
[EC to fat] Therefore, Ya=Vy ・Sya=4X2/10' =8/10
' After passing through the deflection electrodes 36 and 37 by (m) = 8 (w*), it moves upward in the Y-axis direction (deflection direction). That is, the ink reaches the recording paper 11 at a position moved by 12 (im) in the deflection direction from the axis of the ink ejection direction of the head 10.

When the uncharged ink passes between the deflection electrode plates 36 and 37, it is not deflected and travels straight along the axis of the ink ejection direction.

That is, while the ink particles ejected from each ink ejection path 8at pass between the deflection electrodes 36 and 37, the flight direction of the charged ink particles and the non-charged ink particles are separated, and the non-charged ink particles are directed toward the recording paper. 11, the charged ink particles are captured by a gutter 38 installed in front of the recording paper 11, pass above this gutter 38, and collide with the recording paper 11.

As described above, according to this embodiment, the injection of charge into the ink in each ink jetting path at the tip of the head is controlled by a semiconductor laser beam, and the ink is charged/uncharged, so that each nozzle is individually placed in front of the head. Ink load ff1l! There is no need to install poles, and the number of nozzles in the head can be reduced to about 20001
You can increase the number and record. Even when using a laser exposure scanning device as described above, its optical power is
The semiconductor laser output of an electrophotographic laser printer is sufficient. As the light irradiation means, for example, a slit exposure optical system that simultaneously projects one line of the original image can be used in addition to such a laser exposure scanning device.

〔Effect of the invention〕

In any case, according to the present invention, a charged electrode outside the head can be omitted, high-density dot recording can be performed in the recording line direction, and even when a laser exposure scanning device is used, the optical power can be exceptionally high. High resolution and high speed recording can be achieved with low power light irradiation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of the present invention. Figure 2 shows the ink recording of Figure 1 as II-I.
FIG. 3 is an enlarged sectional view taken along the I line. FIG. 3a is an enlarged sectional view of the portion indicated by the two-dot chain line 9■ in FIG. FIG. 3b is an enlarged perspective view of the ink ejection path 8ai at the tip of the lower half 6 of the ink recording head 10. FIG. FIG. 4a is a plan view showing the molecular structure of the components of the charge generation layer 3 shown in FIG. 3. FIG. FIG. 4b is a plan view showing the molecular structure of the components of the charge transfer layer 4 shown in FIG. 3. FIG. FIG. 4c is a plan view showing the molecular structure of components contained in the ink. FIG. 5 is a time chart showing the relationship between laser exposure scanning and ink pressure m movement applied by the vibrator 35 in the ink recording apparatus shown in FIG. l: Nesa glass (transparent substrate) 2: conductivity m<surface) 3
: Charge generation layer 4:1! Cargo transfer layer (3,4
: Photoconductor) 5: Protection [6 2 Lower half 7 2 Electric 11 (electrode) 8: Sheet 8ai:
Nozzle partition wall 8bi: Ink ejection path (ink ejection path) 9: Head base 9a: Light receiving slit 10: Ink recording head ll: Recording paper 1
5: Light source 16: First cylindrical lens 17: First mirror 18 Nisferical lens 19: Polygon mirror 20; Second mirror on motor S 21: Second cylindrical lens 22: Mirror 23:
Photo sensor 30; laser exposure scanning device (light irradiation means)
31: Upper body 32: Vibration plate 33.34
: Bimorph piezo element 35 : Vibrator (vibrator) 36.
37: Deflection electrode (deflection electrode) 38 Nigata (gutter)
39 Nibraten 40: Ink tank 41: Ink cartridge 42: Pump 43: Fucumulator 44: Solenoid switching valve 45: Pump
50: Ink supply device (ink supply means) 51;
Power supply circuit (load pressure power supply circuit) 52: Excitation circuit
53: Power supply circuit (deflection voltage power supply circuit) 54
: Ink flow path (ink flow path) %4a figure '9Jt, b figure

Claims (1)

[Scope of Claims] A light-transmitting substrate with an electrically conductive surface, a photoconductor bonded to the surface, a member forming an ink jetting path along the surface of the photoconductor, and a member having an ink jetting path coexisting with the substrate. an ink recording head including an electrode that acts to form an electric field, an ink flow path for supplying ink to the ink ejection path, and a vibrator that applies pressure vibrations to the ink in the ink flow path; an ink supply means for supplying ink at a pressure; a charging voltage power supply circuit that applies a voltage between the substrate surface of the ink recording head and the electrode; irradiating light corresponding to an image onto the photoconductor through the transparent substrate; a light irradiation means for emitting light; a deflection electrode located in front of the ink ejection path and facing each other with a flight trajectory of ink particles ejected from the ink ejection path therebetween; a deflection voltage power supply circuit that applies a deflection voltage between the deflection electrodes; An ink recording apparatus comprising: a gutter that captures ink particles ejected from a path and passed between the deflection electrodes whose deflection due to an electric field between the deflection electrodes is either greater than or equal to a predetermined value or less than a predetermined value.