JPS6045436B2 - recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording device that records information on a document onto a recording medium, and particularly to a recording device that can perform recording in a controlled state depending on the condition of the document. It is.

In conventional recording devices, such as electronic copying devices, the illuminance of the document illumination lamp remains at a value determined at the time the device was designed.

Therefore, users have controlled the exposure amount by manually adjusting the opening amount of the lens diaphragm or exposure slit each time depending on the density of the document. This manual adjustment is troublesome for the user, and it is difficult to obtain a copy with the desired density in one go; it is only possible to obtain a copy with the desired density after performing the operation many times. It is. This not only takes time for the user, but also wastes copy paper. The present invention has been made in view of the above points, and it is an object of the present invention to provide a recording apparatus that can automatically set optimal recording conditions according to the density of an original image. That is, the present invention provides an exposure means for exposing an original image, a reciprocating means for exposing and scanning the original image by moving relative to the original image, and a recording method based on the exposure scanned image by the reciprocating means. a plurality of process means including a recording means for recording an image on the material; a detection means for measuring the density of the original image and detecting the maximum and minimum values of the density of the original image; control means for optimizing the operating conditions of the process means according to the maximum and minimum values of the original image density;
The control means detects and detects the maximum and minimum values of the original image density during the movement of the reciprocating means, and the control means detects the maximum and minimum values of the original image density during the second movement of the reciprocating means performed after the first movement. The present invention provides a recording apparatus characterized in that image recording is performed based on operating conditions of the process means that are optimized according to the detected maximum and minimum values.

In order to facilitate understanding of the present invention, an outline of the entire apparatus will first be explained.

FIG. 1 shows a typical embodiment of an electronic copying apparatus to which the present invention is applied. The drum 1 has a photosensitive surface, and is arranged in the middle of the machine box so as to be rotatable in the direction of the arrow (clockwise) in the figure by a means such as a motor. The document is placed on a document table glass 2 that constitutes a document placement surface on the top surface of the machine case, and the document table glass 2 is fixed to a document table 3. The document table 3 is arranged by means such as a motor, clutch, pulley, wire, etc., and is also connected to the machine box by means such as a slide rail or rollers, so that it can be moved smoothly in the left and right directions in the drawing. It is becoming. The home position of the original platen 3 is the position shown by the chain double-dashed line in the figure (symbol 3''), and the original is first placed with the left edge of the original platen glass 2 as a reference. When the copy start signal is input, the original is placed. The table 3 moves to the right in the figure (symbol A) until the left end of the document platen glass 2 passes over the document exposure area (the document exposure start position shown by the solid line in the figure), then reverses and moves to the left (symbol B)
Start moving to . When the document table 3 moves in the direction B, the process elements operate so that the document image is formed on the photosensitive surface on the surface of the drum 1. At this time, the original is illuminated by the illumination lamp 4, and its image is projected onto the mirror 5 and the in-mirror lens 6.
The image is formed on the imaging section 7 on the surface of the drum 1 through the . The surface of the drum 1 is uniformly charged by the primary charger 9, and then when it reaches the imaging section 7, it is imaged as described above, and at the same time,
The static electricity is removed by the static eliminator 10. Next, full exposure lamp 1
1, the entire surface is exposed to light, and an electrostatic latent image is formed on the drum surface. Next, the liquid is transformed by the developing electrode 16 of the developing device 14, and the remaining liquid is squeezed out by the aperture charger 17. The visible image on the drum 1 from which the liquid has been squeezed by the aperture charger 17 is transferred onto the copy paper 12 fed from the paper feed section 8 by the transfer charger 18 . The copy paper 12 onto which the visible toner image has been transferred is then separated from the drum surface by a separating section 13, guided to a fixing section 15, fixed thereon, and then discharged onto a tray 19. On the other hand, the remaining toner on the drum surface is cleaned by a blade cleaner 20 pressed against the drum surface, making it possible to perform the next cycle again. After the document table 3 moves in the B direction by the required document exposure distance, it is immediately reversed, reaches the original home position, and stops there. In the vicinity of the document exposure section, there is a photodetection element 21 fixedly disposed on the main body with its detection surface facing the document exposure section. The detection element 21 detects the reflected light of the original image irradiated by the illumination lamp 4 during movement from the aforementioned home position to the original exposure start position. At this point the process elements are inactive so no image appears on the drum. Based on the output from the detection element 21, the exposure amount during actual document exposure can be controlled. This method detects the original density during a part of the back-and-forth movement of the original table, and then exposes the original at the optimal exposure state for the original density in the subsequent steps, resulting in a reduction in copying speed. This is an effective method without any problems. The configuration, control means, etc. of the above-mentioned photodetecting element will be described below.

A conventionally known photoelectric conversion element can be used as the above-mentioned photodetection element.

The photodetecting element 21 in FIG. 1 is located within the required original exposure area.
One or more are provided. When only one is provided, as shown in FIG. 2a, the photodetecting element 21 detects document information in the shaded area 102a of the document 102 on the document table.

A in the figure shows a case where the original is small, and the original is detected over the entire area in the moving direction.

If the document is larger than the distance from the document table's home position to the document exposure start position, as shown in FIG. The document information is detected, but only part of the document's movement direction is detected. In the case of figures A and b, the entire document information is detected even in a part of the document. Therefore, this method is extremely economical and effective when considering output adjustment, assembly man-hours, etc. since only one detection element is required for a document whose entire document information can be determined from only a portion thereof. FIG. 3 shows a control circuit in this case.
Optical information obtained by continuously detecting the shading state of the original image by the photodetecting element 21 is further converted into an electrical signal by the detection circuit 103. The document information converted into electrical signals in this manner is applied to the holding circuit 104, which is composed of a first holding circuit 104a and a second holding circuit. This first holding circuit 104a selects the signal with the highest density (original information signal when the light detection element receives the least amount of light) from among the density information of the original sent from the detection circuit 103. It consists of a peak hold circuit that holds . Further, the second holding circuit 104b selects the signal with the lowest concentration (the document information signal when the most amount of light is received by the photodetecting element),
There is a peak hold circuit that holds this. That is, the aforementioned holding circuit 104 selects the highest value and the lowest value of the original density within one scan of the original 4 and holds them respectively. Reference numeral 105 indicates a differential amplifier, in which the first,
Since the outputs of the second holding circuits 104a and 104b are applied to their inputs, a control output is derived according to the difference between the outputs of the first and second holding circuits.

This control output is applied as an illuminance control signal to the illuminance control circuit 101 that controls the illuminance of the illumination lamp 4 via the gate 106. Further, to another input of this gate 106, a reference power source 107 is applied for applying a control voltage to the illuminance control circuit 101 such that the illumination lamp 4 emits a predetermined reference illuminance. That is, a control signal is sent to the control terminal 108 of the gate 106 to apply the output of the differential amplifier 105 to the illuminance control circuit 101 when the document table 3 moves in the direction of arrow B, and when the document table 3 moves in the direction of arrow A. When moving in the direction, the outputs of the differential amplifier 105 and the reference power source 107 are selectively applied to the illuminance control circuit 101 by applying a control signal such as applying the output of the reference power source 107 to the illuminance control circuit 101. There are things that are. This control signal is reset by, for example, a copy start command signal (using this signal as a trigger signal, the document table 3 starts moving in the direction of arrow A), and is driven when the document table 3 reaches a predetermined position. It can be formed by the output signal of a flip-flop that is reset by the output of a microswitch (the document table 3 starts moving in the direction of arrow B when the drive of the switch is used as a trigger signal). As is clear from the above explanation, if the circuit shown in FIG. Based on the information received, copies can be made while controlling the copying machine. The signals in the holding circuits 104a and 104b can be cleared every time the document is scanned (each time the document table 3 completes one reciprocating movement), but if the same copy is to be made many times, it is recommended that they be kept as they are. is also possible. In this case, the holding circuit may be cleared only when the cover is opened, in conjunction with the opening and closing of the document cover. r FIG. 4 shows another example of the arrangement of the detection elements.

In FIG.
1-1, 21-2, 21-3, . . . , 21-1.
12-1, 112-2, 112-3,...112-1
, information is detected. If the original is larger than the original detection area, the photodetecting element 21-1,
21-2, 21-3, . . . , 21-1 are the shaded areas 112-“, 112-2”, 112-3”, . . . of the original 112”.
, 112-1'' is detected. Originals 112, 112
If the shading of "" varies significantly depending on the location, a single photodetecting element may not be able to accurately capture the information on the document depending on where it is placed. In such cases, it is effective to arrange a plurality of photodetecting elements as shown in Fig. 4.If it is desired to detect document information more accurately, the number of photodetecting elements may be increased.In a case such as Fig. 4b, In any case, the entire area of the document cannot be detected, so in this case, the document should be placed on the glass of the document table 3 in advance so that the information area most desired to be detected is placed above the detection area.

FIG. 5 shows a control circuit using a plurality of photodetecting elements as shown in FIG. 4.

Detection circuits 103-1, 103-2, . . . , 103- having the same functions as those explained in FIG. 1 is provided to convert the density information of the original into an electrical signal.

Furthermore, the outputs of the respective detection circuits 103-1 to 103-1 are applied to integration circuits 114-1 to 114-1 and integrated by the circuits. The integrated signal is applied to a holding circuit 115 having the same function as the holding circuit 104 shown in FIG.
conversely, the signal corresponding to the lowest concentration is output from output terminal 1.
It is output from 15b. These two signals are sent to the differential amplifier 1
05, and a signal proportional to the difference is output. Using this output signal, the exposure amount of the original can be changed in the same manner as described in FIG. When the integrating circuit 114 is used in this way, information is not recorded in the periphery of the document, such as the shaded areas 112-1 and 112-i, and information is not recorded in the central area of the document, such as the shaded area 112-1. -2～11
This is suitable for use when information is recorded in 2-1-1.

Of course, the integration circuit 114 can be completely removed and used in the same manner as explained in FIG. 2.

Furthermore, since the circuit shown in Figure 5 detects multiple locations on the original and also compares all detected amounts, it is possible that some parts of the original may have extremely high (or low) concentrations. However, it is possible to obtain the contrast of information averaged over the entire document without being influenced by this. Note that in FIG. 5, parts given the same numbers as in FIG. 3 have the same structural functions.

Another example of the configuration of the detection element will be described with reference to FIG.

A plurality of photodetecting elements 21-1, 21-2,..., 21
-1 is reciprocatingly vibrating in the width direction of the original 122 (in the direction of the arrow in the figure) at a constant period and with a constant amplitude. Therefore, the detection areas 122-1, 122-2, . . . , 122-1 of the original 122
The area becomes a meandering area as shown in the figure. This method is useful because the shading of the manuscript information varies greatly depending on the location.
Individual inspection. It is effective when the detection elements cannot detect the entire document, and it is also characterized in that it can detect an area equivalent to almost the entire document with a relatively small number of detection elements. An embodiment for causing reciprocating vibration of the detection element shown in FIG. 6 is shown in FIG. 7! be. In FIG. 7, a member 123 to which the photodetecting elements 21-1, 21-2, . . . , 21-1 are fixed is fixed to a slide plate 124.
The slide plate 124 is a stay 1 fixed to the main body side plate, etc.
The spring 12 is slidably disposed along the guide groove 125a of the spring 125, and one end of the spring 12 is fixed to the stay 125.
6. On the other hand, the member 123 is the spring 1
It is in contact with an eccentric cam 127 on the 26 side, and the cam 127 is fixed to the output shaft of a motor 128. motor 1
28 is fixedly disposed on the stay 125 by a mounting plate 129. Eccentric cam 127 by motor 128
If the rotation occurs, the detection elements 21-1 and 21-1 correspond to the difference in eccentricity.
21-2, . . . , 21-1 reciprocate in the direction of the arrow in the figure. As for output control from a plurality of detection elements as shown in FIG. 6, a method similar to that described in FIG. 5 can be used. Furthermore, in the method shown in Fig. 6, if the eccentricity of the eccentric cam is set so that the amplitude is relatively large,
Needless to say, depending on the original, the above-mentioned effects can be obtained even by disposing only one detection element. As described in FIGS. 3 and 5, it is of course possible to control the brightness of the illumination lamp 4 that illuminates the document depending on the detected state of the document. The brightness of the photosensitive drum 1 may be kept constant, and instead of this, the slit width of the slit light irradiated onto the photosensitive drum 1 may be controlled.

That is, as shown in FIG. 8, a slit adjusting plate 203 having an opening having a width D is provided in a part of the optical path of the slit light, and the slit adjusting plate 203 is adjusted so that it can rotate around point 0. In place of the illuminance control circuit 101 in FIGS. 3 and 5, this slit adjustment plate 20 is used.
It is also possible to provide an angle control circuit for controlling the angle θ of No. 3, and to use this angle control circuit to determine the angle θ of the slit adjusting plate 203 in accordance with the output of the differential amplifier 105.

Furthermore, a comparison circuit is provided that compares the output EO of the differential amplifier 105 with a predetermined reference value ESl. For example, when the output EO is smaller than the reference value ES (when the density difference in the original is small), For copying, increase the contrast above the specified value so that the information is clear even when multiple backgrounds overlap. 2
The angle θ of 03 may be increased).

Similarly, a second reference value ES2 may be determined in advance, and when the output EO of the differential amplifier is larger than this ES2, the contrast may be lowered than the desired value.

Further, in the above embodiment, an embodiment in which the document table moves is described, but it is of course applicable to an embodiment in which the optical system moves.

Furthermore, in addition to controlling the amount of beam light irradiated onto the photosensitive drum, it is also possible to control the primary charging voltage, the developing bias voltage, the voltage applied to the transfer charger, etc.

As described above, according to the present invention, the maximum and minimum values of the original image density are detected immediately before image recording, and the operating conditions of the process means are optimized according to the detected maximum and minimum values. Since image recording is performed under the specified operating conditions, there is no change over time in the operating conditions of the process means from original image density measurement to image recording, and image recording can always be performed under optimal operating conditions. It becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of a copying machine to which the present invention is applied, FIG. 2 is an explanatory diagram of the detection area of a document when one photodetection element is used, and FIG. FIG. 4 is an explanatory diagram of the detection area of the document when a plurality of the detection elements are used; FIG.
The figure is a control circuit diagram that performs recording control based on the detection output in FIG. 4, and FIG. 6 is an explanatory diagram of the detection area of the document when a plurality of the detection elements are used and the document is further vibrated back and forth in the width direction.
FIG. 7 is a perspective view of the drive device for the photodetecting element in FIG. 6, and FIG. 8 is an explanatory diagram of exposure amount control using a slit.

Claims (1)

[Claims] 1: an exposure means for exposing an original image; a reciprocating means for exposing and scanning the original image by moving relative to the original image; a plurality of process means including a recording means for recording, a detection means for measuring the density of the original image and detecting the maximum and minimum values of the density of the original image, a maximum value and a minimum value of the original image density detected by the detection means; comprising a control means for optimizing the operating conditions of the process means according to the minimum value;
The detecting means detects the maximum value and the minimum value of the original image density during a first movement of the reciprocating means performed after a recording operation start command, and the controlling means detects a maximum value and a minimum value of the original image density after the first movement is completed. During the second movement of the reciprocating means, image recording is performed based on operating conditions of the process means that are optimized according to the maximum and minimum values detected during the first movement. recording device.