JPS59133082A - Image recording method - Google Patents

Abstract

PURPOSE:To reduce troubles and rejection ratio in a head, by a method wherein a plurality of arrays capable of the same operation are provided, and when an element in one of the arrays is non-operative, an element in other array is operated, in a recorder using a light-emitting element array or the like. CONSTITUTION:Two LED element arrays 2a, 2b are provided in parallel with and adjacently to each other and in the axial direction of a photo-sensitive drum 3, and light emitted from each element 1a, 1b is detected by a sensor 9 through a half-mirror 9a. When the array 2a is operative, an image signal from an image signal outputting circuit 6 is impressed on a driver 5a through an AND circuit 7, and the array 2a is driven. On the other hand, when an LED element 1X in the array 2a is troubled and can not be turned ON, the image signal and an output from the sensor 9 do not accord with each other, and an output from a comparator 10 becomes ''1'', so that an AND circuit 8 is turned ON, and the AND circuit 7 is turned OFF by an inverter 11.

Description

TECHNICAL FIELD The present invention relates to an image recording method in a recording apparatus using a light emitting element array or an optical shutter element array as a print head.

Prior Art A large number of light-emitting elements such as light-emitting diodes, liquid crystals, or optical shutter elements (such as one-seat optical effect elements) are arranged as a print head, and an image pattern on a photoreceptor is formed by dots corresponding to image signals. A recording device has been proposed.

One of the current problems in putting this type of printing apparatus into practical use is poor retention due to the element array used in the print head.

That is, for example, in the case of a light emitting diode (hereinafter abbreviated as LED) array, a large number of elements 1 are arranged to form an array 2 as shown in FIG. It has a configuration in which the light from the arrays 2 is formed into an image on the photosensitive drum 3 via the lens 4, and the image IB corresponding to one line is formed by a plurality of arrays 2.
It is preferable that the number of arrays 2 is small because it is very troublesome in terms of processing signals - it is necessary to finely adjust the positions between each array. Furthermore, in order to obtain high resolution, it is desired to increase the density of the elements 1 by reducing the dimensions of each element 1 and the pitch of their arrangement.

Therefore, for element arrays such as L li D, higher density and an increase in the number of elements in one array 2 are essential conditions. For example, even if it is about 99.9%, when the number of elements reaches 2,000 to 400,011fd, the quality of a single array becomes extremely low at around 10%, leading to an increase in manufacturing costs. It is known that if variations in light and wind, changes in the output of the LED elements due to temperature, etc. are taken into account, the yield rate of arrays will drop significantly.

Such problems also apply to recording devices in which liquid crystals and magneto-optic effect elements are arranged in an array and used as an optical shutter type print head, and many elements are commercialized as a 1'm array. This is a common problem on the above.

Purpose of the Invention The present invention was made in order to eliminate the above-mentioned inconveniences in manufacturing print heads, and to reduce the failure rate of print heads of recording devices and to improve the quality of print heads at the time of manufacture using a simple method. It is an object of the present invention to provide an image recording method that can improve the image processing rate.

Example Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 2 and 3, two rows of L E 1) element arrays 2 a and 2 b are arranged parallel to each other and adjacent to each other and coaxially with the photosensitive drum 3 . And L E I
) The LED stacker elements of the twin array 2a and the LED stacker elements of the LED element array 2b are arranged so that they are in the same scanning dot orientation, and each LED element 1a and 1b has an independent wiring part IC so that drive control is possible.
is connected. In addition, two rows of LED cord arrays 2a
and LED elements 1 located opposite each other in 2b.
Since the images a and 11] are arranged close to each other, they are imaged at substantially the same point on one photosensitive drum 3.

Reference numeral 9 denotes a sensor for detecting light from each of the LED elements la and 1b, and is configured to receive light from a half mirror 9a provided between the lens 4 and the photosensitive drum 3. There is.

FIG. 4 shows a control circuit used in the embodiment shown in FIGS. 2 and 3, with 5a and 5b indicating the LED element array 2a,
The driver 6 that drives the lighting circuit 2b is an image signal output circuit that serially outputs an image signal representing an image to be printed according to a clock signal, and the output terminal of the image signal output circuit 6 is connected to one input of an AND circuit 7.8. The terminal number is connected. The output terminals of each AND circuit 7.8 are connected to the drivers 5a and 5i, respectively.

10 is a sensor 9 that outputs sequentially according to a clock signal.
This is a comparator that sequentially compares the output signal of the sensor 9 and the output of the image signal output circuit 6, and when the output of the sensor 9 and the output of the image signal output circuit 6 match, it outputs "O", and when they do not match, it outputs "O". Outputs “1”.

The output terminal of the comparator IO is connected to the other input terminal of the AND circuit 8 (this is connected to the other input terminal of the AND circuit 7 via the inverter 11).

From the above configuration number, when the LED array 2a is full, the output of the sensor 9 and the output of the image signal output circuit 6 match, the output of the comparator 10 is 0'', and the output of the inverter 11 is 61''. As a result, the AND circuit 8 is turned off, and the AND circuit 7 is turned on, and the image signal from the one-image signal output circuit 6 is applied to the driver 5a via the AND circuit 7, and the LE
The D-shaped clove array 2a is moved.

On the other hand, if one of the LED elements in the LED array 2a, for example, IX, fails and does not light up, the output of one image signal output circuit 6 at the driving timing of the element IX is l", and -LED element lX Even if a command is issued to turn on the light, the LEI element 1X will not light up.Therefore, the sensor 9 will not receive light - its output will be 0", and the output of the comparator 10 will be 1". When turned on, the image signal is applied to the driver 51) through the AND circuit 8, and the LED element I is selected.
LEI corresponding to Iliu. In this circuit, the arrays 2a and 2b are the same as in the embodiment shown in FIG.

This method is applied in cases where there is no substantial shift in the image line even if the timing is driven.

FIG. 5 shows another embodiment of the invention, and the same parts as in FIGS. 2 to 4 are given the same reference numerals.

In FIG. 5, the LED arrays 2a and 2b each have an LED array arranged in a row, and the LED arrays 2a and 2b are arranged coaxially with the photosensitive ram 3 and facing each other. - They are arranged with mirrors 20 in between. The mirror 20 reflects the light emitted from the LED array 2ab at a reflection angle of 45 degrees, and projects the light onto the photosensitive drum 3 via the imaging lens 4.

The three LIiD elements and the two LED elements in the arrays 2a and 21), which are located in mutually opposing positions, are connected to the photosensitive drum 3.
They are driven with an appropriate difference in direction IL1 so as to expose the same point on the top.

FIG. 6 shows a control circuit applied to the embodiment of FIG.
6 is the same first image signal output circuit as the one omitted in Fig. 34, 6' is the second image signal output circuit, and the 211!i
7 image signal output circuit 6 is the output 7 of the first image signal output circuit 6.
The image signal is output with the same content as , but with a slight delay of 1 ffl per image. This delay time corresponds to the time required for the drum surface to move - the amount by which the image forming point of the photosensitive drum 3 shifts due to the positional shift of the LED array 2ab.

The output terminal of the first picture signal output circuit 6 is connected to the driver 5aJ that operates the LED stack array 2a on the normally operating side, and is also connected to the comparator 10 via the -buffer 13.

Reference numeral 14 denotes a storage device for storing data indicating a faulty LED element, and when the comparator 10 detects that one element of the LED array 2a is faulty, the data corresponding to the faulty LED element is stored. It stores the position information of the fault L E I) and outputs a timing signal "work" at which the light in the array 2b corresponding to the failed element should light up. The output terminal of the first related device 14 is connected to one input terminal of the AND circuit 16.

The other input terminal of the AND circuit 16 is connected to the second signal output circuit 6'ζ.
The output terminal 6 is a driver 51 for the LED cumulative element I2b.
), and when the output of the storage device 14 becomes 1'', the image signal of the second picture signal output circuit 6 is added to the driver 5b, and the output of the cable array 2b is It is designed to drive specified elements inside.

Note that 17 is a clock pulse generation circuit that generates a clock pulse e for processing the image signal and faulty element detection in association with each other.

Next, the operation 1 and tips of this embodiment will be explained.

Normally, image signals are sequentially applied from the circuit 6 to the driver 5a in synchronization with the clock pulses generated by the clock pulse generation circuit 17, and the driver 5a receives this image (J No. G Therefore, the driving of the LED child 7k/i2a is controlled for one line.

As a result, an image is formed on the photosensitive drum 3 via the LED X array array 2a, the mirror 20, and the imaging lens 4. Further, this light is reflected by the mirror 9a and is also imaged by the sensor 9c line by line.

Each light receiving element of the sensor 9 outputs a light receiving signal of "■" when it receives light, and "0" when it does not receive light.

This light reception signal is latched and input to comparator 1 ().
It is compared with the image signal manually inputted from the first picture signal output circuit 6 via the line buffer memory 13 every line. Each comparator 10 compares the input light reception signal and image signal in correspondence with each other and sequentially outputs the comparison results according to the clock signal. In this case, if the image signal is 1'', the corresponding LED element 1a lights up, so the value 1'' of the comparator 10 is O''.

Isai, r-El) - x child A L' (some LEL in 2a)
When the A-child IX fails and becomes unable to emit light, this r-+=
Even if a lighting signal of "1" is inputted to the D string element IX from the driver 5a, the LED cumulative element does not light up.

Then, no light reaches the light-receiving element of the sensor 9 corresponding to the failed LED element IX, and the light-receiving signal becomes "O". - 10,000, since the image number 1 corresponding to the faulty LED cumulative element is l'', the output of the sensor 9 and the first image, the comparator l0, is the clock number corresponding to the position of the element. The number "1" is sent to the recording device 14.

Note that the device 14 outputs a clock pulse (therefore the I signal “■” from the comparator 10 is LE I) f=Child IX
is stored in the location corresponding to . The notes are output from the device 14 at the timing of the corresponding dot positions from the image signal output circuit 6 based on this stored position information.
l" is applied to one input terminal of the AND circuit 16, and the second image is input to the driver 5bi through the AND circuit 16. As a result, L
L E I) element I Light is projected onto the same point as the image point.

The above operation is performed every time one line of the image is scanned, and failure L+;. I) Even if confectionery IX is not lit, IX
' lights up on the photosensitive drum 3 (in this embodiment, before the image forming operation, the LED elements 1a on the photosensitive drum 3) are lit and the LED elements 1a on the non-lighted area are controlled.
The position of the non-lighted D element 1a is stored in the storage device 14f, and the output of the recording device 14 is sent to the AND circuit 6 during image forming operation. ,
LEI) The corresponding LED child 1b of the triplet array 2b may be driven.

Next, a description will be given of an embodiment of a recording apparatus using a BRINOTOHETS F in which magneto-optic effect elements are arranged as optical shutter elements.

In FIG. 7, in order from the photosensitive drum 3, the projection lens 4, the optical shutter device 21, the photoconductive member 22, and the halogen lamp 23 cover the imaging area in the axial direction of the photosensitive drum 3. The light from the 46-lead halogen lamp 23, which is installed parallel to and on the same plane as the area of the guide plate, is transmitted to the optical shack device 21 via an optical transmitter 22.

The optical shutter device 21 includes an optical shutter confectionery array using magneto-optic effect elements and a drive control circuit '3 for the same, and controls the switching of the transmitted light for each element according to an image input signal, and controls the switching of the light transmitted through the photosensitive drum 3. This forms a latent image pattern.

Details of the optical shutter element array using magneto-optic effect elements are shown in FIGS. 8 and 9, but specifically LISA512 manufactured by Philips Corporation is provided. A magneto-optic effect element can operate the shutter by heating the shutter part to a predetermined temperature and applying a magnetic field in this state.
wig t-1;

FIG. 8 is a diagram of the shutter element array viewed from the direction of light incidence.

Figure $8 (here, shutter sweets AI, - A2,...
- An is arranged intermittently along the axial direction of the photosensitive drum 3 to form an array 24a. Similarly, one array 24b includes shack elements IS arranged with an interval l.
1, 132, . . . Bn arrays 24a and 24
b forms a set of shutter element arrays.

The confections A l to A n north and B1-130 of A L/A 24a and 24b are arranged in a staggered arrangement with each other (this is a single stroke array 24a and 241). Therefore, the aperture ratio of the shutter is almost 100%. You can get jllll. As for the image signal, even number dots and odd number dots may be separated and both arrays 24a and 24b may be driven with an appropriate time difference. The same applies to the LED clove array, but if the static charge cannot be uniformly removed from the photoreceptor surface due to bright spots, reverse development is performed by matching the dots in the image area of characters and figures to the bright spots. I prefer this power.

In Figure 8, the array 2 4 a =
Similarly to 24b, the relays 24 (, 24d-1i are installed with one shunter cable C1=C2, -Cn J6 and I), D2----Dn are shunt elements A1 to An
ji,; and B1 to Bn. These arrays 24C and 24d form a set of Shack element arrays, which can be driven and controlled once in response to an image signal, similarly to the array 24a=241) described above.

Each shutter element Al~An-Bl~B11=C1
n-Dl~Dn is the heater 2 connected to its corner
5 ii! After heating according to the il image input signal,
When an electric field is applied using the magnetic coils 26 arranged around the entire arrays 24a, 24b, 24C124d, the light sent from the optical image 3A body 22 is transmitted and a bright spot is formed.

In normal operation, for example, the shutter element B2 exposes the instantaneous exposure point of the shutter element A2 on the photosensitive drum 3, and the axial exposure area on the photosensitive drum 3 is Everything is covered. In addition, the shutter elements A1 and C1, A2 and C2, facing each other,...
-A n and Cn- and 131 and D I, 132 and B2
-...13n and Dn expose the same point on the photosensitive drum 3'2, and the same area as the exposed area of the arrays 24C and 24d (from which the arrays 24-a and 24+) is exposed. A latent image pattern can be formed.

In the above configuration, typically arrays 24.2 and 241)
operates to form a latent image pattern, but if the shutter elements in the arrays 241 and 24b, for example 133, fail and do not transmit light, the exposure point Q on the photosensitive drum 3 of the shutter element 133 is image defects occur. In this case, the normally inactive array 24C and
24d, the shutter element D3 located opposite the failed shutter element 133 is activated with an appropriate time difference to change the exposure point of the shutter element B3 to the shutter element B3.
to prevent image defects from occurring.

FIG. 9 shows an example in which the four columns of shutter element arrays arranged in the same manner as in FIG. 8 are connected by a common electrode 27 to enable the same control as described above. That is, for example - shutter element C for the connection point of shutter elements A2 and B2;
1 and Dl are commonly connected by an electrode 27, and when the shutter element A1 fails, the shutter element C1 is operated to prevent the shirt from sagging, as in the case of FIG. 8.

As a result, image defects including wiring pattern failures can be prevented.

In addition, if there is a malfunction in the shutter element array; if the child is in a light-blocking state, use the spare shutter element located opposite it (this allows both dark and bright spots to be selectively displayed; The malfunctioning child shines light ;llj
When using J', '4, always use 1l even if you use a spare element.
This causes the inconvenience that only li points are displayed. In this case, a heating element was provided to heat the entire shutter element array by utilizing the magneto-optic effect element's ability to block light by applying a magnetic field after heating it to a constant temperature a. After applying a magnetic field to bring all the shutter elements, including the faulty element, into a light-blocking state, each shutter element can be activated in response to the image input signal ζ.

Effects of the Invention According to the present invention, the failure rate of print heads due to element failures or manufacturing defects, or the failure rate during manufacturing, is greatly reduced by an order of magnitude as described below.

For example, in the conventional L1'', IJ-based Mitsuko array, L1
! : D element array is 2], 00 L E I)
LE I) The defective rate during the manufacturing of the cable is 0.
, 1%, the rate of non-defective LED element arrays during manufacturing is 100 (1-0, 1/100) E l) Elements are connected in parallel for the print head's pre- 4It & L J!:
Unless the D element and the corresponding LED 91n are defective at the same time, the device will not be defective. Therefore, even if the defective rate of the elements themselves is the same, the non-defective rate of L E I) element array is 22100 (1-(0,1/100)) X100=99.
8%, which is significantly the same as above.

As detailed above, according to the present invention, in one image recording apparatus, two or more elements or the same point on the photoreceptor are exposed simultaneously in response to a common image input signal ζ.
A plurality of arrays of light emitting elements or light shutters are provided in a printhead, and a pattern of bright spots is formed and imaged onto a photoreceptor, typically using only a particular array of the arrays. When a thread element in a row becomes inactive (this means that the corresponding element is activated and normality is established).7.
The formation of a latent image pattern eliminates the drawbacks of conventional devices of this type, such as failure of one element to cause image defects and render the entire print head unusable. It is possible to significantly reduce the failure rate of print heads or the defective rate of print heads during manufacturing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a conventional print head using LE]) z-rays, FIG. 2 is an LED stacker element row diagram showing an embodiment of the present invention, and FIG. FIG. 4 is a perspective view showing an embodiment of the present invention in a printing spatula
Figure 5 is a block diagram showing the control circuit of the print head shown in Figure 3 - Figure 5 is a sectional view showing another embodiment of this output in a print head using the FIG. 5 is a block diagram showing the control circuit of the print head, FIG. 7 is a perspective view showing the configuration of the print head using an optical shutter element, and FIG. 8 is an embodiment of the present invention in the print head shown in FIG. 7. FIG. 9 is a layout diagram showing a simplified example of the wiring of the optical shutter element array shown in FIG. 8. 1... LED cumulative element...L'ED element array, 3... Photosensitive drum, 4... Projection lens, A1~8n, Bl~Bn-C1~Cn-J) IND n
---Shutter element-24a-24b, 24C224
d... Shutter collection array patent applicant Minolta Camera Co., Ltd. Patent attorney Aoyama Aogai (2 persons) Figure 7 Figure 8 Figure 9E]

Claims (1)

[Claims] (1) Light emitting elements or optical shutter elements are arranged in an array in the axial direction of the photosensitive drum, and photosensitive 1:
In an image recording apparatus configured to expose a light image corresponding to input image information on a ram, a plurality of light emitting elements or optical shutter elements may be arranged in plural arrays so that the plurality of light emitting elements or optical shutter elements can operate in the same manner in response to common input image information. Array arrangement is such that each corresponding element on a plurality of array rows has the same connection (
Exposure operation is performed using a particular array row in one row so that the quadrant G is imaged (thus, when an element in the array row becomes inactive, another 1. An image recording method comprising controlling to activate corresponding elements in an array column.