JP2000168145A - Image-recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-recording apparatus which has high resolution and high recording efficiency. SOLUTION: A recording part 2 has a first recording head array 21 where first recording heads 11 each having a first LED array 31 are arranged in an array, a second recording head array 22 where second recording heads 12 each having a second LED array 32 of LEDs disposed between the LEDs of each first LED array 31 are arranged in an array, a third recording head array 23 where third recording heads 13 each having a third LED array 33 are arranged in an array so that the third LED arrays 33 are disposed between the first LED arrays 31, and a fourth recording head array 24 where fourth recording heads 14 each having a fourth LED array 34 of LEDs set between the LEDs of the third LED array 33 are arranged in an array so that the fourth LED arrays 34 are between the second LED arrays 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image recording apparatus for recording an image on a recording material such as a photosensitive film or an electrostatic drum.

[0002]

2. Description of the Related Art As one type of such an image recording apparatus,
2. Description of the Related Art A wet electrophotographic apparatus is known. This wet electrophotographic apparatus records an electrostatic latent image by irradiating a photoconductive layer formed on an outer peripheral portion of an electrostatic drum with a light beam, and thereafter, the photoconductive layer is mixed with toner powder and a non-conductive solvent. The electrostatic latent image is developed as a toner image by utilizing the electrophoresis of the toner powder by bringing the toner into contact with a liquid toner composed of The developed toner adhered to the photoconductive layer is transferred to printing paper or the like in a subsequent transfer step.

In such a wet electrophotographic apparatus, a recording head used for recording an electrostatic latent image by irradiating a photoconductive layer with a light beam has a recording head in a direction parallel to the axis of the electrostatic drum. LED (Light-Emitt)
In addition, there is known an array including a (ing Diode / light-emitting diode) array and a gradient index lens array arranged in a direction parallel to the axis of the electrostatic drum (for example, Journal of the Institute of Electrophotography Vol. 37, No. 37). No. 1: issued March 10, 1998).

The gradient index lens array has a number of gradient index lenses arranged in an array. As such a gradient index lens array, for example, a selfoc lens array (a trademark of Nippon Sheet Glass Co., Ltd.) is known. Further, the gradient index lens is a GRIN lens (GRindex Index le).
ns), which bends and condenses light rays by the gradient of the refractive index inside.

[0005]

In the LED array used for such a recording head, it is difficult to make the pitch between the LEDs less than 20 μm due to the conditions such as the bonding wire and the layout of the LED driver. is there. For this reason, in the recording head using this LED array, the resolution is set to 1200 dpi (dot).
Per inch) or less is difficult.

Further, in the case of using a gradient index lens, the resolution is limited and the transmission of light is less than that of a normal lens (a lens having a uniform refractive index and a curved surface). There is a disadvantage that the recording efficiency is poor due to the low rate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an image recording apparatus having high resolution and high recording efficiency.

[0008]

According to the first aspect of the present invention, there is provided an image recording apparatus comprising a plurality of LEDs arranged at a constant pitch.
A plurality of first recording heads each having a first LED array having a constant pitch and a focusing lens for focusing a light beam emitted from each LED in the first LED array on a recording surface. A plurality of first recording head rows arranged in a row and a plurality of rows arranged at a constant pitch in parallel with the first LED array and arranged between the LEDs in the first LED array. Of the second LED array, and each L in the second LED array.
A second recording head row having a plurality of second recording heads having an imaging lens for forming an image of a light beam emitted from the ED on a recording surface at a constant pitch. .

According to a second aspect of the present invention, there is provided an image recording apparatus comprising: a first LED having a plurality of LEDs arranged at a constant pitch;
ED array and each LE in the first LED array
A first recording head row in which a plurality of first recording heads each having an imaging lens for imaging a light beam emitted from D on a recording surface at a constant pitch; A second LED array consisting of a plurality of LEDs arranged in parallel at a fixed pitch so as to be arranged between the LEDs in the first LED array;
A second recording head having a plurality of second recording heads each having a fixed pitch and having an imaging lens for imaging a light beam emitted from each LED in the second LED array on a recording surface.
A recording head array and a plurality of LEs arranged at a constant pitch
A third recording head having a third LED array made of D, and an imaging lens for imaging a light beam emitted from each LED in the third LED array on a recording surface.
A plurality of third recording heads arranged at a constant pitch in a state parallel to the first recording head row and such that the third LED array is disposed between the first LED arrays; A row, in parallel with the third LED array,
And a plurality of LEs arranged at a constant pitch so as to be arranged between the LEDs in the third LED array.
D, and a fourth recording head having an imaging lens for imaging a light beam emitted from each LED in the fourth LED array on a recording surface.
Fourth recording heads arranged in a plurality of rows at a constant pitch so as to be parallel to the second recording head row and so that the fourth LED array is arranged between the second LED arrays. And a row.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a wet electrophotographic apparatus as an image recording apparatus according to the present invention.

In this wet electrophotographic apparatus, an electrostatic drum 1 having a photoconductive layer as a recording surface formed on an outer peripheral portion thereof, and an electrostatic latent image is recorded by irradiating the electrostatic drum 1 with a light beam. The present invention comprises a recording section 2 which is a characteristic part of the present invention, and an impression cylinder 3 which winds and rotates a printing sheet.

A charging unit 4 for charging the outer peripheral portion of the electrostatic drum 1 is provided on an outer peripheral portion of the electrostatic drum 1, and a liquid toner supply for supplying liquid toner to the outer peripheral portion of the electrostatic drum 1 is provided. A cleaning unit 6 for removing toner remaining on the outer peripheral portion of the electrostatic drum 1 and a charge removing unit 7 for removing static from the outer peripheral portion of the electrostatic drum 1 are provided.

In this wet electrophotographic apparatus, the outer peripheral portion of the electrostatic drum 1 rotating counterclockwise in FIG.
First, it is charged by the action of the charging unit 4. Next, the recording unit 2 scans the outer peripheral portion of the electrostatic drum 1 with a light beam,
An electrostatic latent image is recorded on the photoconductive layer on the outer peripheral portion of the electrostatic drum 1. Then, in the liquid toner supply unit 5, the photoconductive layer of the electrostatic drum 1 on which the electrostatic latent image is recorded comes into contact with the liquid toner composed of the toner powder and the non-conductive solvent, so that the toner powder is The electrostatic latent image is developed as a toner image by electrophoresis. This toner image is transferred to the printing paper wound around the outer peripheral portion of the impression cylinder 3.

Next, the configuration of the recording unit 2 which is a feature of the present invention will be described. FIG. 2 is a side view of the recording unit 2, and FIG. 3 is a partially exploded perspective view of the recording unit.

The recording section 2 includes a first recording head row 21 composed of a plurality of first recording heads 11 arranged in a direction parallel to the axis of the electrostatic drum 1, and a row in a direction parallel to the first recording head row 21. A second recording head row 22 composed of a plurality of second recording heads 12 provided, a third recording head row 23 composed of a plurality of third recording heads 13 arranged in a direction parallel to the second recording head row 22,
A fourth recording head row 24 composed of a plurality of fourth recording heads 14 arranged in a direction parallel to this.

As shown in FIG. 3, the first recording head 11 includes an LED substrate 40 having a first LED array 31 composed of a plurality of LEDs 30 (see FIG. 5) described later,
A normal lens (a lens having a uniform refractive index and a curved surface) for imaging a light beam emitted from each LED 30 constituting the LED array 31 on the photoconductive layer formed on the outer peripheral portion of the electrostatic drum 1 ), A lens barrel 44 for housing the imaging lens 43, a lens holder 42, and a bracket 45. Note that the first L
Each of the LEDs 30 constituting the ED array 31 is based on an image signal transmitted from an image signal generating unit (not shown).
Emit the modulated light beam.

The first recording head 11 is provided on the electrostatic drum 1
The first recording head array 21 is formed by arranging a plurality of rows at a constant pitch along a line base 46 extending in a direction parallel to the axis of the recording head. At this time, as shown in FIG. 4, each first recording head 11
The length L of the first LED array 31 in the direction parallel to the axis of the electrostatic drum 1 is the first length of the first recording head 11.
Is set to be equal to the distance P between the LED arrays 31.

The second, third and fourth recording heads 12,
13 and 14 also correspond to the first recording head 1 shown in FIGS.
1 has the same configuration as that of FIG. However, the second, third, and fourth recording heads 12, 13, and 14 have second, third, and fourth LEDs, respectively.
Array 32, 33, 34 or second, third, fourth LE
The arrangement of the LEDs 30 constituting the D arrays 32, 33, and 34 is different from that of the first recording head 11.

FIG. 5 shows the first, second, third, and fourth recording heads 11, 12, 13, and 14 of the first, second, third, and fourth recording heads.
Fourth LED arrays 31, 32, 33, 34 and first, second, third, fourth LED arrays 31, 32, 3
It is explanatory drawing which shows the arrangement | positioning relationship of each LED30 which comprises 3 and 34.

As shown in FIG. 1, the first LED array 31 includes a plurality of LEDs 30 arranged at a constant pitch. In addition, the second LED array 32
The first LED array 31 includes a plurality of LEDs 30 arranged in parallel at a constant pitch so as to be arranged in parallel with each other and between the LEDs 30 in the first LED array 31. That is, the first LED array 31
And the LEDs 30 forming the second LED array 32 are arranged in a staggered arrangement.

Similarly, the third LED array 33 is composed of a plurality of LEDs 30 arranged at a constant pitch. Further, the fourth LED array 34 includes a third LED
The third LED array 33 includes a plurality of LEDs 30 arranged in a row at a constant pitch so as to be arranged in parallel with the array 33 and between the LEDs 30 in the third LED array 33. That is, each LED 30 forming the third LED array 33 and each LED 30 forming the fourth LED array 34
The EDs 30 are arranged in a so-called staggered arrangement.

At this time, the third LED array 33 is in a state of being parallel to the first LED array 31 and the third LED array 31.
The ED array 33 is arranged so as to be arranged between the first LED arrays 31. That is, the first LED array 31 and the third LED array 33 are arranged in a so-called staggered arrangement.

Similarly, the fourth LED array 34 is
In a state parallel to the LED array 32 and the fourth LE
The D array 34 is arranged so as to be arranged between the second LED arrays 32. That is, the second LED array 32 and the fourth LED array 34 are arranged in a so-called staggered arrangement.

Further, in order to easily control the recording start timing of each light beam scanning, the first LED array 31 and the second LED array 32 are arranged in the circumferential direction of the drum.
, The distance between the second LED array 32 and the third LED array 33, and the distance between the third LED array 33 and the fourth LED array 34 at the same pitch (equal angle when viewed from the axis). It is preferable to arrange them.

In the recording section 2 having such a configuration, the first, second, third, and fourth LED arrays 31, 3
The light beams emitted from the LEDs 30 constituting the components 2, 33 and 34 are imaged by the imaging lens 43 on the surface of the photoconductive layer formed on the outer peripheral portion of the electrostatic drum 1.

At this time, as described above, the first LED
Since each LED 30 in the array 31 and each LED 30 in the second LED array 32 are arranged in a so-called staggered arrangement, a scanning line by a light beam emitted from each LED 30 in the first LED array 31 The recording of the electrostatic latent image on the photoconductive layer is performed in a state where it is located between the scanning lines by the light beams emitted from the respective LEDs 30 in the two LED arrays 32. Similarly, each LED 30 in the third LED array 33 and each LE 30 in the fourth LED array 34
Since D30 is arranged in a so-called staggered arrangement, a scanning line based on the light beam emitted from each LED 30 in the third LED array 33 becomes a light beam emitted from each LED 30 in the fourth LED array 34. , The electrostatic latent image is recorded on the photoconductive layer. Therefore, the first,
Second, third, fourth LED arrays 31, 32, 33, 3
The electrostatic latent image can be recorded with a resolution twice as high as the pitch of each LED 30 constituting the LED 4.

Then, the first LED array 31 and the third LED array 33 are arranged in a so-called staggered arrangement, and the second LED array 32 and the fourth LED array 34 are arranged in a so-called staggered arrangement. Therefore, it is possible to execute scanning at a time over a wide range without cutting the scanning area in the direction parallel to the axis of the electrostatic drum 1.

The first, second, third, and fourth recording head arrays 21, 22, 23, and 24 do not necessarily need to be arranged in this order. That is, as in the embodiment shown in FIG. 5, the first, second, third, and fourth LED arrays 31, 3
Instead of arranging 2, 33, and 34 (that is, the first, second, third, and fourth recording head arrays 21, 22, 23, and 24) in this order, they may be arranged in the order shown in FIG. It may be. In this case, the first, second, third, and fourth LED arrays 3 correspond to the rotation of the electrostatic drum 1.
The irradiation order of the light beams from the first, second, third, and fourth recording head arrays 21, 22, 23,
24 will be changed to correspond to the arrangement order.

In the above-described embodiment, the first, second, third, and fourth four sets of LED arrays 31, 32, 3
3 and 34, each LED 30 in the first LED array 31 and each LED 30 in the second LED array 32
30 in a staggered arrangement, and each LED 30 in the third LED array 33 and the fourth LED array 34
Are arranged in a staggered arrangement. However, for example, the first to sixth sets of six LED arrays are used, and each LED constituting one of the first to third three sets of LED arrays is replaced with another LED.
Arranged between each LED constituting the array,
LED constituting one of the three sets of LED arrays constitutes each LED constituting the other LED array.
It may be configured to be arranged between the EDs.

Similarly, in the above-described embodiment,
First, second, third and fourth four sets of LED arrays 31, 3
Using 2, 33, 34, the first LED array 31 and the third LED array 33 are arranged in a staggered arrangement,
The second LED array 32 and the fourth LED array 34 are arranged in a staggered arrangement. However, for example, the first
6 to 6 sets of LED arrays, and 1 to 3
One of the LED arrays of the set is disposed between the other LED arrays, and the fourth to sixth sets of L
One of the LED arrays in the ED array is
It may be configured such that the D array is arranged therebetween.

In the above-described embodiment, the case where the present invention is applied to a wet electrophotographic apparatus has been described. However, the present invention is applied to other electrophotographic apparatuses and other image recording apparatuses such as an image setter. It is also possible.

[0032]

According to the image recording apparatus of the present invention, since the image is recorded by using the first and second recording head arrays, the image of the present invention according to the second aspect can be recorded. According to the recording apparatus, since the image is recorded using the first to fourth recording head arrays, it is possible to execute the recording of the image with high resolution and high efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a wet electrophotographic apparatus as an image recording apparatus according to the present invention.

FIG. 2 is a side view of the recording unit 2.

FIG. 3 is an exploded perspective view showing a part of a recording unit 2;

FIG. 4 is a plan view showing a part of a first recording head array 21.

FIG. 5 shows first, second, third, and fourth recording heads 11, 1;
1st, 2nd, 3rd, 4th LE in 2, 13, 14
FIG. 3 is an explanatory diagram showing an arrangement relationship between D arrays 31, 32, 33, and 34 and respective LEDs 30 constituting first, second, third, and fourth LED arrays 31, 32, 33, and 34;

FIG. 6 shows first, second, third, and fourth recording heads 11, 1;
1st, 2nd, 3rd, 4th LE in 2, 13, 14
FIG. 3 is an explanatory diagram showing an arrangement relationship between D arrays 31, 32, 33, and 34 and respective LEDs 30 constituting first, second, third, and fourth LED arrays 31, 32, 33, and 34;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic drum 2 recording unit 3 impression cylinder 4 charging unit 5 liquid toner supply unit 6 cleaning unit 7 static elimination unit 11 first recording head 12 second recording head 13 third recording head 14 fourth recording head 21 first recording head row 22 second recording head row 23 third recording head row 24 fourth recording head row 30 LED 31 first LED array 32 second LED array 33 third LED array 34 fourth LED array

Claims (2)

[Claims] 1. A plurality of LEDs arranged at a constant pitch
A plurality of first recording heads each having a first LED array having a constant pitch and a focusing lens for focusing a light beam emitted from each LED in the first LED array on a recording surface. A plurality of first recording head rows arranged in parallel with the first LED array and arranged at a constant pitch so as to be arranged between the LEDs in the first LED array; A second recording head having a second LED array made up of LEDs and an imaging lens for imaging a light beam emitted from each LED in the second LED array on a recording surface at a constant pitch. An image recording apparatus, comprising: a plurality of second recording head rows. 2. A plurality of LEDs arranged at a constant pitch
A plurality of first recording heads each having a first LED array having a constant pitch and a focusing lens for focusing a light beam emitted from each LED in the first LED array on a recording surface. A plurality of first recording head rows arranged in parallel with the first LED array and arranged at a constant pitch so as to be arranged between the LEDs in the first LED array; A second recording head having a second LED array made up of LEDs and an imaging lens for imaging a light beam emitted from each LED in the second LED array on a recording surface at a constant pitch. A plurality of second recording head arrays, a third LED array including a plurality of LEDs arranged at a constant pitch, and each L in the third LED array.
A third recording head having an imaging lens for imaging a light beam emitted from the ED on a recording surface, in a state parallel to the first recording head row, and wherein the third LED array is A plurality of third recording head rows arranged at a fixed pitch so as to be arranged between the first LED arrays; and a state in which the third LED arrays are arranged in parallel with the third LED arrays. And a fourth LED array including a plurality of LEDs arranged at a constant pitch so as to be arranged between the LEDs, and a light beam emitted from each LED in the fourth LED array is recorded on a recording surface. A fourth recording head having an imaging lens that forms an image in parallel with the second recording head row, and the fourth LED array is disposed between the second LED arrays. Multiple at a certain pitch An image recording apparatus comprising: a fourth recording head row arranged in a row.