JPS6389356A - Recording head - Google Patents

Abstract

PURPOSE:To enable a good registration image to be obtained by accurate correction even though any snaking occurs, by detecting a lateral position of a recording medium at the upper part of a recording head by loading at least a portion of an optical system composing a positional sensor on the end part of the recording head. CONSTITUTION:Dielectric recording paper is illuminated by shedding a LED lamp 20 thereon and the reflected light is condensed with a lines 22 via a mirror 21 to form an image on a line CCD 23. In the output of the line CCD 23, a waveform as given in the figure is observed. Then, when the dielectric recording paper 15 starts to travel, the output of the line CCD 23 deflects laterally because of unevenness at the time of cutting of a recording paper edge 18 and of snaking which may slightly be generated. Figure (b) indicates a state at a certain time point, and the dielectric recording paper 15 is indicated to be snaked rightward by 10 bitX14mu=0.14mm from the initial position. In that case, a dielectric recording head 11 is to be moved in the arrow C direction in the figure by 0.14mm and cyclically observed so that the recording start position from the edge 18 of the dielectric recording paper 15 always comes to the same position to correct the snaking.

Description

Detailed Description of the Invention Field of the Invention The present invention relates to a recording head for recording an image on a recording medium in a facsimile machine, a broctor, etc. It relates to a recording head for recording.

2. Description of the Related Art Conventionally, there have been recording devices that record images on the same portion of a recording medium multiple times and overlay them to complete a single image, such as those that achieve color by thermal transfer, or There are some that achieve color by electrostatic recording, but in all of them, the recording head is a line head, that is, the heating elements or electrodes that form the image are arranged in a line or in a staggered manner in the width direction of the recording medium. Normally, each color is superimposed by the reciprocating movement of the recording medium to form a color image.

FIG. 8 shows a conventional example of achieving color by electrostatic recording, and this will be explained.

Regarding these methods, please refer to Japanese Patent Application Laid-Open No. 57-1141.
58, JP-A-57-122455, or JP-A-59-
Learn more about 105660.

In FIG. 8, 1 is an electrostatic recording head, 2 is an electrostatic recording paper, and 3 is a developing device 3BK, 3C containing developers of different colors.
, 3M, and 3Y, 4 is a drive roller, 5 is a reversing motor, 6 is a sensor for detecting a tracking line or edge of the recording paper, and 7 is a sensor for detecting a registration mark on the recording paper. In this apparatus, first, when the drive roller 4 is driven by a motor (not shown), the electrostatic recording paper 2 is conveyed in the direction of arrow A.

At this time, the developing device 3BK supplied with a predetermined color, for example, black toner, of the developing device 3 is brought into contact with the electrostatic recording paper 2, and at the same time, an image signal is applied to the electrostatic recording head 1 to form an electrostatic latent image. is formed, and then a black image is obtained by passing the recording paper through the developing device 3BK. After recording and developing a predetermined length, when the reversing motor 5 is activated, the electrostatic recording paper 2 advances in the direction B and returns to the original roll.
A second color image is obtained by bringing the colored developer 3C into contact with the electrostatic recording paper 2, forming a latent image on the electrostatic recording with 7 dos 1, and developing it with the developer 3C. A color image is obtained by repeating this process as many times as there are developing devices.

The problem with obtaining such color images is registration, and registration marks 8 are placed at the edges of the screen as shown in Figure 9, so that each image matches even if the paper expands, contracts, and meander. , print the tracking line 9 with the electrostatic recording head 1 or print it from the beginning, measure the pitch P of the registration mark 8 with the sensor 7, and if there is vertical expansion or contraction of the paper, change the recording cycle. to form an image, adjust the vertical registration of the image, observe the tracking line 8 with the sensor 6, and if a horizontal shift occurs in the recording paper 2, move the electrostatic recording head 1 left or right or use the electrostatic Although the recording head 1 is fixed, there are recording heads that move only the image signal to perform lateral registration and achieve a color image.

Problems to be Solved by the Invention However, with this configuration, there is a problem in that even a slight meandering of the recording paper causes lateral registration to fail.

The reason for the above-mentioned problem is that there is a distance in the recording paper conveyance direction between the detection position by the sensor 6 and the recording position by the electrostatic recording head 1. As is clear from FIG. detected a deviation of △ from the reference value of the tracking line 9 and corrected it by moving the electrostatic recording head 1 in that direction or by moving the image signal given to the recording electrode of the electrostatic recording head 1 by ∆ from its initial position. Even if the distance between the sensor 6 and the electrostatic recording head 1! Therefore, even though it is necessary to further correct δ, since this δ cannot be corrected, it does not match the previous image, and as a result, the width of the AO size recording paper is approximately 0. The present invention has been made in view of the above-mentioned problems, and even if meandering occurs in the recording paper, it can be easily fixed with a simple structure. It is an object of the present invention to provide a recording head capable of achieving lateral registration. At least a part of an optical system constituting a sensor for detecting the lateral position of the recording medium is mounted on the recording medium, and the 0-function is configured to detect the lateral position of the recording medium above the recording head. With the above-described configuration, the present invention has almost no distance in the recording medium transport direction between the detection position of the recording medium by the sensor and the recording position by the recording head, and the distance between the detection position by the sensor and the recording position by the recording head as described above can be reduced. It is possible to eliminate the error δ due to the distance shape between the two, and it is possible to easily perform horizontal registration.

Example Hereinafter, the present invention will be described in detail as shown in the drawings.

FIG. 1 is a perspective view showing an electrostatic recording head 11 according to an embodiment of the present invention.
A recording means consisting of a needle electrode 13 and an auxiliary electrode 14 arranged in a row on the upper surface of the paper 2 is provided, and when forming a latent image on the electrostatic recording paper 15, the needle electrode 13 and the auxiliary electrode 1. Achieve this by applying a voltage. A sensor 16 detects the lateral position of the electrostatic recording paper 15, is attached near the end of the main body 12 of the electrostatic recording head 11, and has a slit 17 on the top surface. The slit 17 on the upper surface is located on an extension of the needle electrode 13, and is arranged so that the center thereof is substantially opposed to the edge 18 of the electrostatic recording paper 15.

The sensor 16, as shown in FIG.
ED lamp addition, a mirror 21 for changing the optical path of the reflected light,
An optical system consisting of a lens n, etc. that collects the reflected light, and a line C that receives and photoelectrically converts the reflected light collected by the lens η.
0D23, the detection position P by the driver's sensor is
The position is selected to be opposite to the upper surface of the main body of the electrostatic recording head 11 and to be directly beside the recording position by the needle electrode 13.

Note that this detection position P does not necessarily have to be directly beside the recording position by the needle electrode 13, but it is preferable that the distance between the detection position P and the recording position in the recording paper transport direction be as small as possible. The cylinder is a sponge roller for pressing the recording paper 15 against the electrostatic recording head 11.

Next, these operations will be explained.

First, when an image is to be formed, an LED lamp m is illuminated to illuminate the electrostatic recording paper, and the reflected light is focused by a lens n through a mirror 21, and an image is formed on a line CCD 23. As a result, the output of the line CCD 23 has a waveform as shown in FIG. 3.

It should be noted that the explanation will be made assuming that the lens n forms an image at the same magnification.

FIG. 3(a) shows the waveform of the edge 18 of the recording paper 15 when forming the first image, and the life CCD 23 is 1
024 bit, 1 bit, 14μ width is used, and the waveform of exactly the 512th bit shows that it changes from Low to High, and an image is formed using this value as the 0 reference. When the electrostatic recording paper 15 starts running, the output of the line CCD 23 changes due to variations in cutting of the recording paper edge 18 and slight meandering.
It can swing left and right. FIG. 3(b) shows a certain point in time, and the output rises from a position 10 bits to the right compared to FIG. 3(a). That is,
First place 10 bits x 14μ = Q, 14m
This shows that the electrostatic recording paper 15 meandered to the right by m.

In this case, a motor (not shown) moves the electrostatic recording head 11 in the direction of arrow C in FIG.
+o+ movement and periodically monitoring so that the recording start position from the edge 18 of the electrostatic recording paper 15 is always at the same position,
Correct meandering. Therefore, since this monitoring is performed until all color processes are completed, an image without color shift can be obtained. Here, the edge detection of the recording paper 15 is performed by the sensor 16 that can detect the position P on the extension of the needle electrode 130 rows of the electrostatic recording head 11. It becomes possible to prevent color shift δ (see FIG. 10) caused by a positional deviation between the position and the position detected by the detection sensor (distance −e in FIG. 8).

As described above, when detecting the lateral position of the recording paper 15 by the process 18 of the recording paper I5, the sponge roller 2-
The width of 1 is 3 on each left and right side with respect to the width of electrostatic recording paper 15.
It is preferable to increase the length by ~4 m. As a result, a very small amount of electrostatic recording paper 15 generated due to meandering, etc.
Prevention II-A prevents wrinkles that occur in the electrostatic recording paper 15 and shifts in the reading position due to slight lifting of the edge 18 of the electrostatic recording paper 15.

Alternatively, instead of forming the slit 17 to allow the reflected light to pass through, the slit 17 may be made of glass that is entirely light-transmissive. By using such a glass, it is possible to reliably prevent errors in the reading position (usually within 5 to 6 bits) caused by the edge 18 of the recording paper 15 falling slightly into the slot H7.

Also, instead of using the sensor 16 to detect the edge of the electrostatic recording paper 15, a tracking line as shown in FIG. 9 is printed on the recording paper, and the sensor 16 detects this to The position may also be detected.

In addition, in the above embodiment, in order to perform left and right alignment,
The electrostatic recording head II is moved in the horizontal direction, that is, in the direction of arrow C, but instead of this, an image signal movement method is used, in which the electrostatic recording head 11 is fixed at a fixed position and the needle electrode printing start position is moved. It is also possible to use a method in which the recording head is shifted from side to side, but in this case, the positioning accuracy is slightly lower than in the electrostatic recording head moving method. This is because, in the case of the electrostatic recording head movement method, it is possible to match the feed amount to the arrangement pitch of 14μ of the line CCD 23, but in the case of the image signal movement force method, it can only be controlled by the needle electrode arrangement pitch. It is for this purpose. When adopting the image signal movement method, it is not necessary to attach the entire sensor 16 to the electrostatic recording head 11 as shown in FIG. Only the mirror 21 and slit 17 (the case of full glass is shown) are attached to the main body 12 of the electrostatic recording head 11, and the remaining parts, such as the LED lamp, lens n1 line CCD 23, etc., are separate members from the electrostatic recording head 11. 2
6 may be maintained. With this configuration,
The structure of the electrostatic recording head 11 can be simplified.

FIG. 5 shows sensors 1 at both ends of the electrostatic recording head 11.
6 (the internal structure is the same as in FIG. 2) is shown.

By arranging the sensors 16 on both sides in this way, it is possible not only to correct the color shift caused by the meandering of the recording paper described above, but also to correct the color shift caused by the humidity change or temperature change that often occurs when forming a color image on the electrostatic recording paper. It becomes possible to correct color shift due to expansion and contraction of 15. For example, the sixth
The figure shows a case where printing is performed on electrostatic recording paper 15 whose humidity has been adjusted to 60% in an atmosphere of 80%, where the horizontal axis shows time and the vertical axis shows elongation in the width direction of the recording paper. First, after printing and developing registration marks (in this case, the tracking line nails on both sides and the registration mark 28 on one side, as shown in FIG. 7), the time required until the electrostatic recording paper 15 is moved back. 1
．． During this period, the electrostatic recording paper 15 elongates the most (elongation amount Bm), and then during black printing time t, elongates b-a, sequentially,
c-b when cyan.

d - c for magenta, e - d ( for yellow)
(not shown), and the rate of change in elongation gradually decreases.

Further, the overall elongation rate is 2 to 3%, and is greatest during mark printing. After mark printing and banking, black printing starts, but before starting black printing, the sensor 16
Measure the width of the two tracking lines τ on the electrostatic recording paper 15 using the line CCDZ3 within, and use this as the initial value.
Print a black image to a predetermined width. After the recording and development of one screen is completed, it is moved back and cyan is recorded, but before this, the width of the two tracking lines is measured again using the line CCD 23. At this time, the width of the tracking line γ has been extended by cd compared to the blank image, so even if it is printed with the same width as the black image, the recording paper 15 has already been extended by this amount (c
This will result in the color shift b). Therefore, c-b
It is necessary to correct the image signal accordingly. This correction is for AO size,
In the case of approximately 900 pharynx width, it is about 1 to 2 stages at most,
In the case of an electrostatic recording head with a linear density of 16 dots/depression, 16
dot/1tan to 32 dots/run, and this dot is equal to the regular number of printing dots, for example, 800.
mmX 16 dots/M= 12800 The image signals are distributed so that the dots are arranged at approximately equal intervals, and printing is performed with the same image signal as the adjacent needle electrodes, so that the entire printing dot
By increasing the number to 12,832 dat, if you record the black image by overlaying it on top of the previously printed black image, the absolute width will not be the regular size, but you will be able to obtain an image with no color shift. By performing this for each color, it becomes possible to obtain an image without color shift. Still recording paper 15
If the dots shrink, contrary to the above, it is possible to correct the color shift by reducing the number of dots. However, in this case, you must be careful about the required dat
(where the black line should be) will fall off, so when using a plotter etc., set the minimum line width line to the line density of the electrostatic recording head, which is 1/1 in this example.
Instead of printing with 1611El11, if you set the minimum line width to twice the line density, 1/8a width (2-bit printing), when shrinking, even if you reduce the number of printing dots, the line will become thinner but will fall off. That will no longer be the case.

In the embodiment shown in FIG. 5, the sensor 16 may also detect edges on both sides instead of detecting the tracking n. Further, in each of the above embodiments, a line CCD was used as a sensor for detecting the edge of electrostatic recording paper or a tracking line, but a normal optical sensor may also be used. Further, although the above embodiments have all been described with respect to an electrostatic recording head, the present invention is not limited to this case, and can be similarly applied to any other recording head, such as a thermal head.

Further, although some of the head configurations have been explained using line heads, it is also possible to use two rows of heads called staggered arrangement. Although not shown, it is also possible to use a Selfoc lens or the like to arrange the mark reading surface and the line CCD 23 in a straight line, instead of bending the optical path at right angles as shown in the drawing. .

Effects of the Invention As is clear from the above description, the present invention provides at least a part of the optical system constituting a sensor for detecting the lateral position of the recording medium at the end of the recording head. By detecting the lateral position of the recording medium above the head, the distance between the detection position of the recording medium by the sensor and the recording position by the recording head in the recording medium traveling direction becomes extremely small, thereby preventing meandering. This has the effect of reliably correcting even when 0.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a part of an electrostatic recording head according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the sensor mounting part, and FIGS. 3(a) and (b) are the above embodiments. FIG. 4 is a cross-sectional view of the same part as FIG. 2 showing another embodiment, FIG. 5 is a perspective view showing an electrostatic recording head of still another embodiment, Figure 6 is a graph showing the amount of elongation of electrostatic recording paper over time, Figure 7 is a plan view showing marks printed on electrostatic recording paper in the embodiment of Figure 5, and Figure 8 is a graph showing the amount of elongation of electrostatic recording paper over time. A schematic perspective view of the recording device, FIG. 9 is a plan view showing marks printed on electrostatic recording paper by the electrostatic recording device, and FIG. 10 shows the tracking line position and sensor position of the electrostatic recording paper and the electrostatic recording head. It is a graph showing the relationship between positions. 11... Electrostatic recording head, 12... Main body, 13...
- Needle electrode, 14... Auxiliary electrode, 15... Electrostatic recording paper, 16... Sensor, 17... Slit, 18...
Edge, 20...LED lamp', 21...Mirror, Shogun...Lens, n...Line CCD Agent's name Patent attorney Toshio Nakao and 1 other person 2nd figure 3rd! ! 1 (a) (b2 v; 4 Figure 5 Figure 6 Figure 6 M7 Figure 8 Y 4

Claims (1)

[Claims] It is equipped with a recording means for recording an image on a recording medium, and a main body holding the recording means, and at least one of an optical system constituting a sensor for detecting the lateral position of the recording medium is provided at an end of the main body. 1. A recording head, characterized in that a portion of the recording medium is mounted on the main body, and the recording head is configured to detect the lateral position of the portion facing the main body.