JPS61135761A - Image recording apparatus - Google Patents

Abstract

PURPOSE:To enable image recording with high reliability by preventing an image from inclining with respect to a transfer sheet, by simple constitution providing a recording head having dielectric layers provided not only between first and second electrodes but also between second and third electrodes. CONSTITUTION:The titled recording apparatus has an image forming means for forming an image on an intermediate recording medium 1 and a transfer means for transferring the image to a transfer sheet 5 by pressure and the image forming means contains a recording head 2 having dielectric layers 30, 31 respectively provided between a first electrode 21 and a second electrode 22 as well as the second electrode 22 and a third electrode 24 and the first direction 21A, toward which the electrode element of the first electrode 2 is extended, is inclined by a minute angle to the axial direction of the aforementioned intermediate recording body 1. By this method, the leading edge of the electrostatic charge pattern formed on the intermediate recording medium 1 corresponding to image information inclines by a minute angle to the axial direction of the intermediate recording medium 1. As a result, when the intermediate recording medium and the transfer means are arranged so as to keep uniform pressure distribu tion therebetween, the image transferred to the transfer sheet is not inclined with respect to said transfer sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus that forms an image on an intermediate recording medium, transfers this image to a transfer paper serving as a transfer sheet, and records the image on the transfer sheet.

This type of image recording has traditionally been carried out in electrophotographic copying machines, etc., and generally a toner image formed on a photoreceptor drum, which is an intermediate recording medium, is transferred to a transfer paper using a corona charger or the like. After the toner image is transferred onto a transfer sheet such as, the transfer sheet is passed through a fixing device to fix the toner image on the transfer sheet and output it.

In this way, in the past, the transfer and fixing of an image onto a transfer sheet were performed using separate devices, but an image recording device that performs transfer and fixing at the same time has been previously proposed (for example, U.S. Patent No. 4, 267.556 etc.).

This image recording device uses a drum having a dielectric layer on its surface as an intermediate recording medium, forms an electrostatic latent image on the surface of the drum according to an image information signal, and uses a toner developer to develop the electrostatic latent image. Visualize it to form a toner image, bring a transfer sheet into contact with the toner image using a transfer fixing roller,
The toner image is transferred from the drum surface to the transfer sheet by pressure, and at the same time, the toner image is fixed onto the transfer sheet by the pressure.

This method of simultaneously performing transfer and fixing is extremely effective in that it simplifies the process, improves the reliability of the apparatus, and allows the apparatus to be made smaller.

□ 11 11 By the way, conventionally, in general fixing devices in which the toner image transferred to the transfer sheet is fixed under pressure by a pair of rollers, uneven pressure distribution in the longitudinal direction of the roller occurs due to the roller being bent by pressure. In consideration of the nature of Place the transfer sheet so that the generatrix intersects at a small angle, and place the transfer sheet perpendicular to the contact line of these two rollers (the roller generatrix intersects at a small angle, so the contact area is a line area rather than a point). It is known that a toner image is fixed by conveying the toner image in a direction. By arranging the rollers in this manner, the pressure distribution in the longitudinal direction of the rollers can be made uniform, uniform fixing conditions can be obtained, and the generation of wrinkles on the transfer sheet can also be prevented.

However, in an image recording apparatus that simultaneously performs transfer and fixing as described above, the generatrix of the drum serving as the intermediate recording medium and the generatrix of the transfer and fixing roller are arranged in order to obtain a uniform pressure distribution, similar to the roller arrangement in the fixing device described above. If you place them intersectingly.

It has been found that the following inconveniences occur. In other words, the transfer sheet is conveyed in a direction perpendicular to the contact line between the drum, which is an intermediate recording medium, and the transfer fixing roller, as described above, but since the drum generatrix and this contact line are inclined at a slight angle to each other, the transfer sheet is The direction of movement of the sheet is the direction of movement of the image formed on the drum (direction perpendicular to the generatrix of the drum)
Therefore, the image (toner image) transferred from the drum to the transfer sheet is inclined with respect to the transfer sheet.

The main object of the present invention is to provide an image recording apparatus that solves the problems of the conventional example, and more specifically, it is an image recording apparatus of a type that pressure-transfers an image onto a transfer sheet. A first object of the present invention is to provide an image recording device in which an image obtained on a transfer sheet is not tilted with respect to the transfer sheet.

A second object of the present invention is to provide an image recording device that has a simple configuration and is capable of recording highly reliable images.

ヱ”L’s I! An image recording apparatus according to the present invention includes an image forming means for forming an image on a rotatable intermediate recording medium, and a transfer means for transferring the image formed on the intermediate recording medium onto a transfer sheet by pressure. , the image forming means includes a first electrode including at least one electrode element extending in a first direction, and a plurality of electrode elements extending in a second direction intersecting the first direction while facing the first electrode. a second electrode consisting of electrode elements; and a second electrode provided opposite to one of the first electrode and the second electrode and corresponding to a plurality of intersections between the first electrode and the second electrode. a third electrode having a plurality of openings; a third electrode having a plurality of openings between the first electrode and the second electrode;
and a dielectric layer provided between an electrode and a third electrode, the first direction in which the electrode element of the first electrode extends is an axial direction of the intermediate recording medium. It is tilted at a small angle. As a result, the leading edge of the electrostatic charge pattern formed on the intermediate recording medium corresponding to the image information is inclined at a small angle with respect to the axial direction of the intermediate recording medium, and as a result, the intermediate recording medium and the transfer means and are arranged so as to maintain a uniform pressure distribution between them, the image transferred onto the transfer sheet will not be tilted with respect to the transfer sheet.

Support 1 The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1 is a sectional view schematically showing essential parts of an embodiment of an image recording apparatus embodying the present invention.

In FIG. 1, a drum 1, which is an intermediate recording medium, is a cylindrical conductive substrate made of metal or the like with a dielectric layer provided on the outer peripheral surface thereof, and is rotationally driven in the direction of the arrow by a driving means (not shown). Digital electrostatic recording device consisting of an ion generator 2
selectively emits ions to the drum 1 according to an image information signal inputted by an image information signal input means (not shown), and forms a dot-shaped electrostatic charge pattern corresponding to the image information on the outer peripheral surface of the drum 1. The details will be described later. Development: A3 is used to visualize the electrostatic charge pattern formed on the drum 1 by the electrostatic recording head 2 using toner as a developer. and a rotatable developing roller. Therefore, the image information signal input means, the electrostatic recording head 2, and the developing device 3 are elements forming the surface of the drum 1, which is an intermediate recording medium.

On the other hand, the transfer paper 5, which is a transfer sheet loaded in the cassette 4, is conveyed one by one into the main body of the apparatus by the rotation of a paper feed roller 6, which is rotatable by a drive means (not shown). By rotating the rotatable register roller 7 at a predetermined timing, the transfer paper 5 and the drum 1 are
Positional synchronization with the image formed above (toner fi) is performed.

In FIG. 1, below the drum 1, there is provided a transfer and fixing device comprising a transfer and fixing roller 9 rotatable in the direction of the arrow and a biasing force applying mechanism such as a spring 11. The transfer and fixing roller 9 is connected to the drum l by a spring 11 whose one end is engaged with the rotating shaft 10.
1, and is pressed against the drum 1 at the transfer and fixing position 8 shown in FIG.

The transfer paper 5 is transferred to the transfer fixing position 8 by the sheet conveyance mechanism described above.
The toner image formed on the drum 1 is transferred to the nip between the drum 1 and the transfer/fixing roller 9F! The image is transferred onto the transfer paper 5 by the pressure of Jl, and at the same time, the image is fixed onto the transfer paper by the pressure. Thereafter, the transfer sheet 5 is separated from the drum 1 by a sheet separating means (not shown), passes through a guide G, and then passes through a discharge roller 1 driven by a driving means (not shown).
2 onto the tray 13.

On the other hand, the surface of the drum 1 after passing through the transfer position 8 is cleaned by a cleaning blade 15 of a cleaner 14 serving as a cleaning means.
The remaining charge on the surface of the drum 1 is then removed by a corona charger 16 in preparation for the next image formation.

Note that the cleaner 14 may not be provided if the efficiency of transferring the toner image to the transfer sheet is good.

Figures 2 and 3 are for explaining the principle of digital electrostatic recording. Figure 2 (a) is a plan view of the digital electrostatic recording head, and Figure 2 (b) is a plan view of the digital electrostatic recording head. FIG. 3 is a sectional view showing a portion of the recording head corresponding to one dot of the electrostatic charge pattern. still.

Digital electrostatic recording, which records images by emitting ions to form an electrostatic charge pattern on a dielectric drum, is known, for example, in U.S. Pat. Nos. 4,155,093 and 4,160.
, No. 257, No. 4,267゜556 or JP-A No. 1983
This is known from No.-53537 and the like.

As shown in FIG. 2(A), the recording head includes a drive electrode 21 consisting of a plurality of electrode elements arranged in parallel and extending parallel to the generatrix LA of the drum 1, and a plurality of drive electrodes 21 extending in a direction crossing the drive electrode 21. Control electrode 2 consisting of several parallel electrode elements
2, and the electrode elements of the drive type 8i21 and the control electrode 22 overlap in the vertical direction (in the direction perpendicular to the plane of the paper in FIG. 2) to form a matrix structure. Control electrode 2
Each electrode element of 2 is preferably formed with a groove or hole 23 along its length, and these control electrodes 22
Each intersection of the electrode element of the drive electrode 21 corresponds to one dot of the electrostatic charge pattern.

Reference numeral IB indicates the rotational direction of the drum I (ie, a direction perpendicular to the bus line IA), and reference numeral 34 indicates a mounting pin of the recording head to the image recording apparatus.

FIG. 3 is a sectional view showing a portion of the recording head corresponding to one dot of the electrostatic charge pattern, in which one electrode element 21a of the drive electrode 21 extends parallel to the generatrix of the drum l, and one electrode element of the control electrode 22 extends parallel to the generating line of the drum l. Element 22a extends in a direction transverse to this.

The recording head further includes a drive electrode 21 with respect to the control electrode 22.
The screen electrode 24 has a screen electrode 24 provided on the opposite side, and screen openings on a plurality of sides are formed in a matrix shape in the screen electrode 24 corresponding to the intersections of the drive electrode 21 and the control electrode 22. FIG. 3 shows one screen opening 2 corresponding to the intersection of electrode element 21a and electrode element 22a.
A dielectric material 30 is provided between the electrode element 21a of the drive electrode 21 and the electrode element 22a of the control electrode 22, and between the electrode element 22a of the control electrode 22 and the screen electrode 24, only shown in FIG.
．． 31 are respectively provided to isolate these electrodes from each other.

Electrode element 21a of the drive electrode and electrode element 22a of the control electrode
An appropriate alternating current voltage (for example, about 1 to 3 KV peak-to-peak) is applied between the electrode element 22a of the control electrode and the dielectric 30, and as a result, a creeping discharge occurs along the interface between the electrode element 22a of the control electrode and the dielectric 30. ions are generated. At this time, an appropriate DC bias (for example, about 300 to 900 V in absolute value) is applied between the electrode element 22a of the control electrode and the conductive base ib of the drum 1.
When the voltage is applied, ions generated by the creeping discharge flow toward the drum 1. If this DC bias is negative, it will be a negative (minus) ion flow, and if it is positive, it will be a positive (plus) ion flow. On the other hand, an appropriate constant bias is applied to the screen electrode 24, and the electrode element 22 of the control electrode
By alternately switching the potential of a to a value before and after the bias value to the screen electrode 24, the generation of ion flow onto the dielectric layer la of the drum l can be controlled. To screen electrode 24 - 35
Assuming that a voltage of 0 V is applied and the potential of the electrode element 22a of the control electrode is switched in two ways: -350 V and -650 V (7), when the voltage is -650 V, negative ions pass through the screen opening 27 of the screen electrode 24. However, when the voltage is -350V, the ion flow is blocked by the voltage of the screen electrode 24, and the dielectric layer 1a is not charged.

As described above, since the screen electrode 24 has a plurality of screen openings formed in a matrix shape corresponding to the matrix structure formed by the drive electrode 21 and the control electrode 22, each electrode element of the control electrode 22 By controlling the potential as described above, it is possible to form an arbitrary dot-shaped electrostatic charge pattern on the dielectric layer la of the drum l. In other words, the intersection between one electrode element of the drive electrode 21 (21a in FIG. 3) and one electrode element (22a in FIG. 3) of the control electrode 22 and the correspondence formed on the screen electrode 24. The combination with the screen opening (27 in FIG. 3) constitutes a recording head element corresponding to one dot when forming an electrostatic charge pattern on the drum 1.

Therefore, when each electrode element of the drive electrode 21 is provided parallel to the bus line IA of the drum 1 as shown in FIG. 2(a),
The dots of the electrostatic charge pattern are arranged in a rectangular arrangement extending along two straight lines perpendicular to the drum generatrix LA and the drum movement direction IB, as shown in FIG. The area in which a charge pattern can be formed is rectangular.

FIG. 4 is a diagram showing the structure of the recording head in an embodiment of the image recording apparatus according to the present invention and the dot arrangement of the electrostatic charge pattern formed thereby, and shows the structure of the recording head in an embodiment of the image recording apparatus according to the present invention. are given the same reference numerals.

The difference between the structure of the recording head shown in FIG. 4 and that shown in FIG. 2 is that in the structure shown in FIG. In the case of FIG. 4, each electrode element of the drive electrode 21 is
Although the recording head extends generally in the direction of the drum l axis, the entire recording head is tilted at a small angle θl (for example, 1 degree to several degrees) with respect to the 1 ram generatrix IA, as shown by the dashed line 21A in FIG. 4(a). This means that the position is relative to l.

The positional relationship of the drive electrode 21, control S electrode 22, and screen electrode 24 in the recording head is the same as that shown in FIG. Therefore, each electrode element of the drive electrode 21 is non-parallel and non-perpendicular to both the drum generatrix IA and the moving direction IB, and each electrode element of the control electrode 22 is also non-parallel to and non-perpendicular to the drum generatrix IA and the moving direction IB. It is also non-parallel and non-perpendicular.

According to the configuration shown in FIG. 4, the dot array in the width direction of the electrostatic charge pattern formed on the drum 1 is inclined by the minute angle θ1 with respect to the drum generatrix IA, as shown in FIG. 4 (b). becomes. Since the drum 1 rotates in the direction of the arrow 1B, the dot row in the length direction of the electrostatic charge pattern becomes parallel to the drum movement direction IB. Therefore, in the image forming area defined on the drum l by the recording head of this embodiment, the leading edge of the pattern is at a small angle θ with respect to the drum generatrix IA.
I is inclined and forms a parallelogram with both side edges parallel to both side edges of the drum I.

FIG. 5 is a diagram showing the configuration of a recording head in an image recording apparatus according to another embodiment of the present invention and an electrostatic charge pattern formed thereby, and members corresponding to those shown in FIG. 4 are the same. The symbol is attached.

The recording head shown in FIG. 5 is different from the one shown in FIG. The drive electrode 21 is shown by a dashed line 21A in FIG. 5(A).
Only each electrode element of
1. It is tilted. The point that each electrode element of the control electrode 22 extends in a direction intersecting each electrode element of the drive electrode 21 is the same as in the embodiment of FIG. Therefore, the drive of the embodiment shown in FIG. The respective electrode elements of the 11F1rt pole 21 and the control electrode 22 are both non-parallel and non-perpendicular to both the generatrix IA and the moving direction IB of the drum I, as in the embodiment of FIG.

Also in the configuration shown in FIG. 5, the dot array in the width direction of the electrostatic charge pattern formed on the drum l is inclined by the minute angle θ1 with respect to the drum generatrix LA, as shown in FIG. 5 (b). . Therefore, in the image forming area defined on the drum l by the recording head of this embodiment, the leading edge is inclined at a small angle θl with respect to the drum generatrix IA, and both side edges are on both side edges of the drum l. It becomes a parallel parallelogram.

FIG. 6 is a diagram showing the relationship between the arrangement of the drum 1 and the transfer fixing roller 9 and the position of the electrostatic charge pattern formed on the drum 1 by the recording head 2 in an example of the image recording apparatus of the present invention. Components corresponding to those shown in FIG. 1 are given the same reference numerals.

As mentioned above, the drum l and the transfer fixing roller 9 are arranged along the axis I of the drum l so as to provide a uniform pressure distribution between them.
C and the axis 9C of the transfer fixing roller 9 are not in the same plane,
The drum generatrix IA and the transfer fixing roller generatrix 9A are arranged so as to intersect at an angle o2 of one to several degrees. Therefore, the nip center line 5C between the drum 1 and the transfer and fixing roller 9 (the contact line between the drum 1 and the transfer and fixing roller 9) intersects the generatrix LA of the drum 1 at a small angle θ3. When the transfer sheet 5 is taken into the nip between the drum l and the transfer fixing roller 9, the leading edge 5A is regulated to be conveyed in a direction perpendicular to the nip center line 5C, and therefore is regulated to be conveyed perpendicularly to the drum generatrix LA. The leading edge 5A of the transfer sheet inclined at the same minute angle θ3 coincides with the nip center line 5C.

As explained with reference to FIG. 5, each electrode element of the drive electrode of the recording head 2 is arranged at a small angle
It is sloping. In the image recording apparatus shown in FIG.
is made to be equal to the minute angle θ3 (that is, each electrode element of the drive electrode and the nip center line 5C are parallel to each other on the drum surface). As a result, as shown in FIG. When an electrostatic charge pattern whose leading edge is inclined at the same minute angle θl with respect to the drum generatrix IA is developed as the drum rotates and reaches the nip center line 5C, the leading edge S of the toner dot pattern after development is at the nip center line. Consistent with 5C.

In this way, the leading edge S of the toner e-dot pattern and the leading edge 5A of the transfer sheet are inclined at the same minute angle θ1 or Q3 with respect to the drum generatrix LA, and the image formation on the drum 1 and the conveyance of the transfer sheet 5 are When these are performed synchronously, the leading edge S' of the dot pattern transferred and fixed onto the transfer sheet 5 by the transfer fixing roller 9 is aligned with or parallel to the leading edge 5A' of the transfer sheet after passing the roller 9.

When a very small inclination is allowed between the image formed on the transfer sheet and the transfer sheet, the angle θl that the drive electrode 21 of the recording head makes with respect to the generatrix LA of the drum l and the nip center line 5C are It is not necessary to make the angle θ3 with respect to the drum bus line IA strictly equal.

In the above-mentioned embodiment, a case was shown in which fixing was performed at the same time as pressure transfer, but the present invention is not limited to this. Pressure transfer is performed using an intermediate recording medium and a roller, and then fixing (not shown) is performed at another position. Of course, image fixing may be performed by other means.

As described above, according to the present invention, even when uniform transfer pressure is obtained, the image on the transfer sheet does not tilt, and this image tilt can be prevented by using an extremely simple structure. can be achieved with.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of an image recording apparatus according to an embodiment of the present invention. Figures 2 and 3 are diagrams showing the principle of digital electrostatic recording. Figure 2 (a) is a plan view of the recording head, and Figure 2 (b) is the electrostatic charge formed by the recording head. FIG. 3 is a plan view showing the pattern, and a sectional view showing a recording head portion corresponding to one dot of the electrostatic charge pattern. FIG. 4 is a diagram showing the structure of the recording head in the image recording apparatus according to the embodiment of FIG. 1, in which FIG. 4 (a) is a plan view of the recording head, and FIG. FIG. 3 is a plan view showing an electrostatic charge pattern. FIG. 5 is a diagram showing the configuration of a recording head in an image recording apparatus according to another embodiment of the present invention, and FIG.
5 is a plan view of the recording head, and FIG. 5(b) is a plan view showing an electrostatic charge pattern formed by the recording head. FIG. 6 is a perspective view showing the relationship between the arrangement of a drum and a transfer fixing roller and the position of an electrostatic charge pattern formed on the drum by a recording head in an example of the image recording apparatus of the present invention. Snow l...Intermediate recording medium (drum) IA...Drum bus line 2...Recording head 5/1e Transfer sheet 9...e Transfer fixing roller 21...First electrode (drive electrode) 21A... Extending direction of the first electrode 22... Second electrode (control electrode) 24.as Third electrode (screen electrode) 30.31-
-Dielectric Figure 2 (A) (B)
Figure 3 Figure 4 (a) (b) Figure 5 (a)

Claims (1)

[Scope of Claims] An image recording device comprising an image forming means for forming an image on a rotatable intermediate recording medium, and a transfer means for transferring the image formed on the intermediate recording medium onto a transfer sheet by pressure. The image forming means includes a first electrode including at least one electrode element extending in a first direction, and a second direction extending in a second direction intersecting the first direction while facing the first electrode. a second electrode consisting of a plurality of electrode elements; and a second electrode provided opposite to one of the first electrode and the second electrode;
a third electrode having a plurality of openings corresponding to a plurality of intersections between the electrode and the second electrode; and a third electrode between the first electrode and the second electrode and the second electrode. and a dielectric layer provided between each of the third electrodes, and the first direction in which the electrode elements of the first electrode extend is relative to the axial direction of the intermediate recording medium. An image recording device characterized by being tilted at a minute angle.