JPH0545990A - Color image recorder - Google Patents

Abstract

PURPOSE:To make the dimension of a recording form constant and to prevent color slurring in a transverse direction, at the time of recording the images of each color by forming an aligning mark and then, setting time for rewinding an electrostatic recording form so that the elasticity of a paper approaches saturation. CONSTITUTION:The motor 3A of a driving roller 3, a rewinding motor 7, and a taking up motor 8 are connected with a controller, and the electrostatic recording form 2 is reciprocated with prescribed sequence. Further, the speed of the electrostatic recording form 2 is controlled with a signal from a humidity sensor 11. The absorbing of the moisture and drying, of the electrostatic recording form 2 is remarkable, on the half-way part of the recording form 2 taken up from a roll to a wider 10, compared with when the recording form 2 is in a roll state. Therefore, travelling time until the recording form 2 is sent out from the roll 2A, to form a mark, and then, taken up on the winder 10, is set at the time required until the recording form 2 absorbs the moisture or is dried, and its elasticity is almost saturated, or more, so that the elasticity can be absorbed. Moreover, the time is drastically different according to the type, moisture content, ambient temp., etc., of the recording form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image recording apparatus for repeatedly reciprocating a recording medium to a recording position to form images of different colors at the same position and superposing them to obtain a color image.

[0002]

2. Description of the Related Art Conventionally, a device shown in FIG. 4 is known as a device for obtaining a color image. In FIG. 4, 101 is an electrostatic head, 102 is an electrostatic recording paper, 102A is a roll of electrostatic recording paper, 103 is a drive roller, and 104 is a plurality of developing devices 104 to which toners of different colors are supplied.
a developing means having a, 104b, etc., 105 is a mark for aligning in the width direction (hereinafter referred to as a CD mark), 1
06 is a mark for aligning the feed direction (hereinafter referred to as MD
Reference numeral 107 is a rewinding motor, 108 is a winding motor, 109 is a head moving motor, and 110 is a winder for winding the electrostatic recording paper.

Color image formation by this apparatus is performed in the following procedure. First, the driving roller 103 rolls the roll 102A.
The electrostatic recording paper 102 is unwound from the sheet and conveyed through the electrostatic head 101. The conveyed electrostatic recording paper 102 is wound around a winder 110 with a constant tension by a winding motor 108. During the transportation of the electrostatic recording paper 102, a voltage is applied to the electrostatic head 101 to form a first color electrostatic latent image on the electrostatic recording paper. At the same time, the developing device to which the toner of the first color is supplied (in FIG. 4, the developing device 104a to which the black toner is supplied) is moved up to be brought into contact with the electrostatic recording paper 102, and the development and visible image Turn into. This process is continued until the recording and development for a predetermined length are completed, and the recorded image portion is entirely wound up on the winder 110.

Next, the roll 102A of electrostatic recording paper is driven by the rewinding motor 107 in the rewinding direction of the electrostatic recording paper,
The original roll 1 is the part wound around the winder 110.
It is rewound on 02A. After that, the electrostatic recording paper 102 is again driven by the drive roller 1 in order to record and develop an image of the next color.
The latent image of the second color is formed by the electrostatic head 101, and is developed and visualized by the developing device 104b to which the toner of the second color (for example, cyan toner) is supplied. Also at this time, the electrostatic recording paper 102 is taken up by the winder 110 until the image recording for a predetermined length is completed, and when this is completed, it is rewound onto the original roll 102A by the rewinding motor 107 again.

By repeating the above steps one after another using the developing devices to which toners of different colors are supplied, the images of different colors are superposed on the same position of the electrostatic recording paper 102 to form a color image. .. The order of forming images of different colors may be any order, but is usually determined by the characteristics of the toner or the characteristics of the developing device.

When a color image is obtained through the above steps, the most important thing to pay attention to is color misregistration, and it is necessary to form images of respective colors so that they are exactly overlapped at the same position. When the electrostatic recording paper is repeatedly reciprocated, the recording paper meanders or expands and contracts. Therefore, in order to correct the position of the image, the CD is usually formed at the time of the first image formation or before it. Mark 105 and MD mark 10
6 is printed. The CD mark 105 corrects the meandering of the electrostatic recording paper, and rewinds after the mark is printed. When a voltage is applied to the electrostatic head 101 for the next color, a photo mark (not shown) is provided. Sensor (usually C
The position of the CD mark 105 is detected by using a CD array), and if the position is deviated from the initial position, the electrostatic head 101 is moved to the head moving motor 10 by an amount corresponding to the position.
By 9, the electrostatic recording paper is moved in the width direction and is corrected so that it is always at the same position even if the meandering occurs.

On the other hand, the MD mark 106 is the electrostatic recording paper 1
02 is for correcting the expansion and contraction in the feeding direction, and the pitch of the MD mark 106 is measured by a photo sensor (not shown). If the pitch is longer than a predetermined length, the recording cycle is delayed, and When the pitch of the MD mark 106 is short, that is, when the electrostatic recording paper is shrunk, the pitch is measured, and the color shift is corrected by recording earlier than a predetermined recording cycle.

[0008]

However, in such a structure, although the electrostatic recording paper is aligned in the feed direction and the lateral direction by the CD mark and the MD mark,
There has been a problem that color misregistration occurs in the width direction of the electrostatic recording paper.

As a result of examining the cause of this problem, the present inventor found the following matters. That is, the electrostatic recording paper is usually adjusted to a predetermined humidity and supplied in the form of a roll, but when this electrostatic recording paper is put on a color image recording apparatus as shown in FIG. Depending on the humidity conditions of, it absorbs or dries and expands and contracts not only in the feeding direction but also in the width direction. For expansion and contraction in the feeding direction, MD mark 10
Although the color misregistration is prevented by the correction by 6, the lateral expansion and contraction cannot be corrected even if the CD mark 105 exists. The reason is that the CD mark 105 is corrected so that the recording start position in the recording paper width direction is constant, and is not corrected for expansion and contraction in the recording paper width direction. Due to the expansion and contraction in the width direction, a large color shift occurs on the side opposite to the recording start position, which is the above problem.

As a method of making the color misregistration in the width direction due to the expansion and contraction in the width direction apparently inconspicuous, the CD mark 105 is printed on both sides of the electrostatic recording paper 102, the pitch between them is measured, and the error in the width direction is measured. A method of allocating to both sides, that is, a method of driving the head moving motor 109 so that the electrostatic head 101 is always at the center with respect to the screen is conceivable.
The error is only distributed to both sides and is not a fundamental solution. Further, since the expansion and contraction of the recording paper depends on the humidity, there is a method of making the usage conditions extremely severe, but it is troublesome for the actual users. There is also a recording medium using a film that is not easily affected by humidity as the recording paper, but in this case, the cost is about 10 times higher than that of a normal electrostatic recording paper, which is a problem.

The present invention has been made in view of the above-mentioned problems, and color misregistration is achieved without controlling the humidity of the working environment and even when a normal electrostatic recording paper is used as a recording medium. It is an object of the present invention to provide a color image recording device capable of obtaining a color image free of color.

[0012]

In order to achieve the above object, the present invention has a conveying means for reciprocating and conveying a recording paper fed from a rolled state, and a plurality of different recording papers. A color image recording apparatus having a recording unit for recording color images in an overlapping manner, wherein the image is recorded prior to image recording.
A mark for aligning each color image is formed outside the image recording area of the recording paper, and after the mark is formed, the running time when the recording paper is rewound is adjusted so that the expansion and contraction of the recording paper approaches saturation. It is designed to be set to the time required for.

[0013]

According to the present invention, with the above-described structure, before recording an image on the recording medium, the recording medium is made to run in the ambient atmosphere and is absorbed or dried until expansion / contraction due to humidity change approaches saturation. Therefore, at the time of subsequent image recording, expansion and contraction due to humidity change does not occur much in the recording medium, and by aligning the recording start position in the width direction, color misregistration can be prevented over the entire width.

Further, since the above-mentioned running for absorbing or drying is performed when the recording paper is rewound to the recording start position after the mark is formed, it is not necessary to empty the recording paper for that purpose, and as a whole, The recording time can be greatly reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color image recording apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic configuration diagram of a color image recording apparatus according to an embodiment of the present invention. 1 is an electrostatic head, 2 is an electrostatic recording paper, 2A is a roll of electrostatic recording paper, and 3 is electrostatic. Driving rollers for conveying recording paper, 4 is a developing means provided with a plurality of developing devices to which toners of various colors are supplied, and 5 is a CD
Mark, 6 MD mark, 7 roll 2A rewinding motor, 8 winding motor, 9 electrostatic head moving motor,
10 is a winder. Since these are basically the same as the conventional one shown in FIG. 4 and the operation of forming a color image is also the same, detailed description thereof will be omitted.

The motor 3A for driving the drive roller 3, the rewinding motor 7, and the winding motor 8 are connected to a controller (not shown), and the electrostatic recording paper 2 is arranged in the sequence shown in FIGS. 3 (b) and 3 (c). Is configured to reciprocate. Further, a humidity sensor 11 for detecting humidity is arranged in this color image recording apparatus. A signal from the humidity sensor 11 is input to the control device and used to control the reciprocating speed of the electrostatic recording paper, which will be described in detail later.

FIG. 2 is a graph showing the relationship between humidity and time of a specific electrostatic recording paper. The electrostatic recording paper is preliminarily conditioned to 60%. Therefore, even in the atmosphere of 60% humidity, the electrostatic recording paper does not expand or contract over time as indicated by the line 50 in FIG. 2, so that an image without color misregistration can be obtained. However, this electrostatic recording paper is
When used in an atmosphere of, the electrostatic recording paper absorbs moisture in the air as shown by the curve 51 and starts to stretch, and during that time, the dimensional change occurs, and the dimensional change stops after a certain time.
As can be seen from the comparison with the curve 52 showing the case where it is placed in an atmosphere of 75%, the time required for the elongation to reach almost saturation is longer as the difference in humidity is larger. On the contrary, the curve 53
As shown in (3), when placed in a low humidity atmosphere of 35%, the electrostatic recording paper dries, which causes shrinkage of the electrostatic recording paper.

Moisture absorption and drying of such an electrostatic recording paper are shown in FIG.
In the above apparatus, the electrostatic recording paper 2 is more prominent in the distance between the roll 2A and the winder 10 than when the electrostatic recording paper 2 is in the roll state. Therefore, the running time until the electrostatic recording paper 2 is unwound from the roll 2A and wound up by the winder 10 after the mark is formed is required until the electrostatic recording paper absorbs moisture or dries and its expansion and contraction almost reaches saturation. Stretching can be absorbed by setting the time longer than the time. The time it takes for the expansion and contraction of the electrostatic recording paper due to humidity changes to reach almost saturation varies greatly depending on the type of electrostatic recording paper, water content, ambient humidity, etc. This information is checked in advance, and this information is input to the control device (not shown) of the device of FIG.

Next, referring to FIG. 3, which is a graph showing the movement of the electrostatic recording paper with time, the image alignment operation according to the present invention will be described. FIG. 3A shows a conventional method, in which the electrostatic recording paper is moved forward for mark printing, back to the original position, forward for black image formation, back to the original position, and cyan image formation. Steps such as forward movement and back to the original position are repeatedly performed, and forward movement and backward movement at this time are performed at the same time.

On the other hand, FIG. 3B shows an embodiment according to the present invention. In this embodiment, the electrostatic recording paper is first advanced to perform mark printing. Next, when the electrostatic recording paper after printing is rewound from the winder 10 onto the original roll 2A, the back speed is slowed down, and during this running, the electrostatic recording paper expands and contracts due to moisture absorption and drying. To make it almost saturated.

The back speed is determined from the detection value of the humidity sensor 11 based on the characteristic of FIG. For example, FIG. 3B shows a case where the humidity is 85%, and FIG.
The case of 5% is shown, and the case of humidity 85% is longer. When the humidity is 60%, of course, expansion and contraction does not occur, so the bag is backed at a normal speed. After a slow back for humidity control, a color image is formed by repeating the steps of advancing forward to form a black image, advancing forward, advancing to cyan image forming, and advancing as usual. In this method, unlike the case where a blank time is provided, when the mark is printed and then rewound, it is slowly rewound. Although it differs from time to time, the lateral dimension is stable and there is no color shift. Even if the absolute dimension in the vertical direction changes, the pitch of the MD mark 6 is constantly measured and corrected, so that color misregistration does not occur.

In the above embodiments, the back time after the mark is printed is based on the time A or B at which the mark reaches almost saturation in the graph of FIG. 2, but these can be changed according to the design concept. For example, in order to completely prevent color misregistration, it is sufficient to slowly take time so as to get closer to the saturation point than the positions A and B in FIG. Also,
On the contrary, when a certain amount of color misregistration is allowed, for example, when a recording width of 1000 mm is allowed and an error of several hundred μm is allowed, it takes time to achieve 50 to 70% of the saturation point. Should be done.

In the above embodiment, the humidity is detected and the back time is set according to the change in the humidity. However, the relationship between the humidity and the back time does not necessarily have to be set strictly, and a certain humidity is set. A rough stepwise setting such as setting a time for the range may be used, and further, a sufficient fixed amount of back time may be provided regardless of the humidity. However, it is preferable to set the back time according to the humidity because the entire image forming time can be shortened.

The humidity sensor 11 used in the above embodiment may be an analog type or a switch which can measure only a certain point. When using a humidity sensor that can measure only 75% at a certain point, that is, 75%, it is possible to set the back time stepwise by arranging a plurality of humidity sensors having different characteristics. In practical use, 2 to 4 pieces are sufficient for use.

The position of the humidity sensor is not limited to being provided inside the apparatus as shown in the drawing, but may be attached outside. Further, instead of controlling the back time according to the detection signal of the humidity sensor, an operation switch capable of manually setting these times may be provided and manually operated by an operator. That is, since the humidity fluctuation does not change drastically in one day, rather than placing a special humidity sensor, the operator sees a normal hygrometer to see if the electrostatic recording paper expands or contracts significantly. It may be determined whether or not, and the back time may be set by the operation switch if necessary.

Further, although the above description is for the case where the electrostatic recording paper is used, the method of the present invention is not limited to the case where the electrostatic recording paper is used. Any method such as an electrophotographic method for obtaining a color image, a heat sensitive method, an ink jet method or the like can be used.

[0028]

As is apparent from the above description, in the present invention, prior to recording an image, the recording medium is run for the time necessary to adjust the humidity so that the expansion and contraction of the recording medium approaches saturation. Even when image recording is performed by repeatedly reciprocating the recording medium, the recording medium does not expand or contract due to moisture absorption or drying, and the dimension of the recording medium in the width direction during image recording of each color becomes constant. The color misregistration is prevented, and a good color image can be obtained.

Further, since the running for absorbing or drying the recording paper is performed when the recording paper is rewound to the recording start position after the mark is formed, it is not necessary to empty the recording paper for that purpose, As a result, the recording time can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a color image recording apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing expansion and contraction characteristics of an electrostatic recording paper in different humidity atmospheres over time.

FIG. 3 is a diagram showing a running state of an electrostatic recording sheet in an example of the present invention and a conventional example.

FIG. 4 is a schematic configuration diagram of a conventional color image recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrostatic head 2 Electrostatic recording paper 3 Driving roller 4 Developing means 5 CD mark 6 MD mark 7 Rewinding motor 8 Winding motor 10 Winder 11 Humidity sensor

Claims (1)

[Claims] 1. A color image having a conveying means for reciprocating and conveying a recording paper fed out from a rolled state, and a recording means for recording a plurality of images of different colors on the recording paper in an overlapping manner. In the recording apparatus, a mark for aligning each color image is formed outside the image recording area of the recording paper before recording an image, and after the mark is formed, the running time when the recording paper is rewound is A color image recording apparatus, wherein the time is set so as to adjust the humidity so that the expansion and contraction of the recording paper approaches saturation.