JPS6240418A - Printer scanner control device - Google Patents

Abstract

PURPOSE:To minimize lowering of processing speed due to switching of rotation speed of a polygon rotating mirror by providing a timing device that rotates a polygon mirror at the second rotation speed which is greater than the first rotation speed for a specified period set longer than a period in which characters related to character code information of one unit on receiving a signal commanding printing. CONSTITUTION:A start signal SS is generated for each character code information for one unit received from a host computer 7. When the start signal SS is outputted, a retrigger monostable multivibrator 103 is started, and only output signals of an osicllator 125 are impressed to a PLL circuit 127 through an OR gate 126, and the PLL circuit 127 controls rotation speed of a motor 6 to make it to a prescribed speed. Time of operation in which output of the retrigger monostable multivibrator 103 is in '1' level is set to become TR which is longer than time TP for printing 1 page of recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a scanner motor control device for driving a polygonal rotating mirror that deflects and scans a light beam such as a laser beam, and particularly to a scanner motor control device suitable for use in a laser printer. Regarding a control device.

Conventional Art For example, some laser printer scanner motors have a system in which a multifaceted rotating mirror is rotated at a predetermined rotational speed during printing, and rotated at a lower rotational speed during standby when printing is not performed. This is to avoid shortening the life of the scanner motor and generating unnecessary noise due to constant rotation of the scanner motor at the high rotational speed required for printing.

Some laser printers are equipped with a character generator that receives character code information from a host machine, converts it into image information, ie, bit information, and sends it to a printing section, ie, a laser drive section, of the printer. Naturally, a certain amount of processing time is required to convert a character code into bit data using a character generator. On the other hand, printing is performed by rotating the scanner motor at the aforementioned predetermined rotational speed.

When a character generator receives a lot of code information from a host machine, it takes a lot of time to convert it. Therefore, unless the processing of the code information received during the printing time is completed, the printing operation is stopped. At this time, the scanner motor is rotated at a low speed. When the code conversion process is completed, the printing operation is restarted and the scanner motor is rotated at the specified rotational speed again. Such a situation frequently occurs when a large amount of code information is received by the character generator, and the rotational speed of the scanner motor changes each time. Since the scanner motor requires a certain amount of time to reach the specified rotation speed from low speed rotation, if the above-mentioned situation occurs frequently, the processing speed of the entire printer will be reduced.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a printer/scanner control device that eliminates the drawbacks of the prior art and minimizes the reduction in processing speed caused by switching the rotational speed of a multifaceted rotating mirror.

Structure In order to achieve the above object, the present invention includes a converting means for receiving character code information and converting it into corresponding bit information, a radar generating means for generating a laser beam modulated according to the bit information, and a polygonal rotating mirror. a scanning means for deflecting and scanning the laser beam by rotating a polygonal rotating mirror; a first predetermined rotation speed for controlling the rotation of the scanning means; and a second rotation speed faster than the first predetermined rotation speed. In a printer scanner control device for printing characters representing bit information, the control device includes a control device for selectively rotating the scanning device at a predetermined rotational speed, and the control device includes a control device for printing characters representing bit information. It has a timer for rotating the polygonal rotating mirror at a second predetermined rotation speed for a predetermined period, and the predetermined period is set longer than the period for printing characters associated with one unit of character code information, and the control The means includes a printer scanner that rotates a polygon mirror, usually at a first predetermined rotation speed, and rotates the polygon mirror at a second predetermined rotation speed for a predetermined period in response to a signal instructing printing. It features a control device.

Note that in this specification, the term "character" shall be interpreted in a broad sense, including not only characters in a narrow sense, but also numbers, symbols, punctuation marks, figures, and the like.

The configuration of the present invention will be described below based on examples.

For example, in a laser printer, an exposure device as shown in FIG. 3 is used. This device includes a semiconductor laser 1 that generates a laser beam modulated according to a recording signal, and a laser beam 2 supplied from the laser 1 that is sent to a photoreceptor drum 5.
In combination with a multifaceted rotating mirror 3 that deflects and scans in the direction, a photosensitive drum 5 whose laser beam deflected and scanned by the multifaceted rotating mirror 3 is continuously scanned in the axial direction, and sequential exposure is performed, and the multifaceted rotating mirror 3. It is configured to include a motor 6 that constitutes a scanner and drives a multifaceted rotating mirror 3.

A laser beam 2 modulated according to a recording signal (given by a data source such as a host conbeater) is generated by a semiconductor laser 1 and is irradiated onto one mirror surface of a polygonal rotating mirror 3. As described later, the polygonal rotating mirror 3 is rotated during printing operation.
rotates at a prescribed rotational speed, and deflects the radar beam 2 by utilizing the fact that the reflection angle of the mirror surface that reaches the incident position of the laser beam 2 changes according to the rotation.

The Radhe beam 2 emitted from the polygonal rotating mirror 3 reaches the surface of the photosensitive drum 5 and is scanned from one end to the other end in the axial direction. As a result, electrostatic latent images are sequentially formed on the surface of the photosensitive drum 5 in accordance with the recording signals.

FIG. 4 shows an example of a control system applied to the device shown in FIG. 3, including an interface 8 that receives recorded information from a host computer 7, and a character controller that converts code information in the received recorded information into bits. 9. A printer controller 10 that controls the motor driver 12 according to the control code included in the received recording information and also controls the radar driver 11 according to the bit information; It consists of a laser driver 11 that drives the radar 1, and a motor driver 12 that rotates the motor 6 at a predetermined rotational speed under the control of the printer controller 10.

In the above configuration, in the standby state in which no recording is performed, the printer controller 10 controls the motor 6 to rotate at a predetermined rotational speed 4 times lower than the specified rotational speed, thereby reducing the driving noise caused by the motor 6, etc. We are trying to

During standby, the printer controls O- and ylo rotate the motor 6 at this low rotational speed.

When record information for one page, for example, is transferred from the host computer 7 to the interface 8 in this state, the character controller 9, which has received the record information via the interface 8, converts the code information into bit information (binary 1 (image information expressed as 0) and output to the printer controller 10. When the printer controller 1G is ready to record, it sends the motor driver 12 to the motor 6.
Outputs a command to increase the 0 rotation speed to the specified speed.

Upon receiving this, the motor driver 12 sets the rotational speed of the motor 6 to the specified rotational speed. Also, printer controller 1o
outputs the bit information converted by the character controller 9 to the v-za driver 11, and the laser driver 11 that receives this drives the semiconductor laser 1 based on the bit information.

In this example, the interface 8 is 9,600 BP.
A data transfer rate of S can be obtained. In this case, 1
It takes approximately 1.1 ms to transfer a character, and time is also required for bit conversion processing by the character controller 9.

Therefore, if the conventional scanner motor control method were applied, if the printing speed of the printer is fast and the number of characters to be printed received by the character controller 9 is large, data transfer and code conversion processing for those characters would be completed. The exposure apparatus must be put on standby, that is, the motor 6 is kept at a speed lower than the specified speed, until the data transfer and code conversion processing are completed, and the motor 6 must be controlled to return to the specified rotational speed. I had to.

In reality, this situation with a large number of received characters often occurs during printer operation, and with conventional methods,
The speed is switched between low-speed rotation and specified speed rotation, but when changing from low-speed rotation to specified speed rotation, it takes time to reach the specified speed rotation, which increases printout time and reduces image quality. This had the disadvantage of shortening the motor life.

Therefore, in this embodiment, by maintaining the scanner motor 6 at a specified rotational speed for a period slightly longer than the printing operation time, even if the above-mentioned condition occurs, the scanner motor 6 is prevented from frequently switching to low-speed rotation. Make sure there is no tail. (7) [Part of the printer controller 10 and motor dryer 1 that realizes the control operation]
An example of the configuration of No. 2 is shown in FIG. 1, and the same parts as in FIG. 4 are indicated by the same reference numerals, so redundant explanation will be omitted.

Therefore, the controller 1o1 that controls the motor driver 102 of the drive system, the motor 10 that drives the photosensitive drum 5, etc.
4 under the control of the controller 101.
02. A time limit circuit that is activated by a start signal Ss instructing printing and outputs a signal for selecting the rotational speed of the motor 6. For example, a retrigger monomulti-nobbler 1
Consists of 03. Note that the printer controller 10
1 also includes a circuit for controlling the laser dry nog 11, but its illustration is omitted in FIG. 1 to avoid complication of explanation.

The motor driver 12 also includes an oscillator 121 that generates a pulse signal that serves as a reference signal in low-speed rotation control, an oscillator 122 that generates a pulse signal that serves as a reference signal at a specified rotation speed, and a retrigger monomultipibrator 10.
Inverter 1 inverts the signal output from 3 and outputs it
23, AND gate 124 which takes the logical product of the output signal of the oscillator 121 and the output signal of the inverter 123, and the output signal of the retrigger monomultiply brake 103 and the oscillator 12
AND gate 125, A
OR to take the logical sum of the outputs of ND gates 124 and 125
PLL (phase locked loop) controls the motor 6 to a predetermined rotational speed by using the pulse signal given from the gate 126 and the OR gate 126 as a speed command and referring to the feedback signal from the motor 6. It is configured to include a circuit 127 and a driver 128 that drives the motor 6 based on the output of the PLL circuit 127.

The operation of the above configuration will be explained based on the timing chart of FIG. First, a start signal S8 is generated from the character controller 9 for each unit of character code information received from the host computer 7, that is, for each page of character code information in this embodiment. When the start signal S3 is output, the driver 102 is driven via the controller 101, and the retrigger mono multivibrator 103 is activated to output a "1" level voltage. Litori Mono Multivibrator 1
The output voltage of 03 is the output voltage of inverter 123
” level, and then apply a “1” level voltage to one input terminal of the AND gate 125. At this time, oscillator 1
21 and 122 are always in an oscillating state, with the only difference being the pulse width and period. Therefore, A connected to the output
If a "1" level voltage is applied to the other input terminal of the ND Dart, the Dart will function. When the output of the retrigger monomultipibrator 103 is "1", the AND key 4124 does not function and the AND key 125 functions, so only the output signal of the oscillator 125 is transmitted to the OR gate. It is applied to the PLL circuit 127 via 126. Therefore, the PLL circuit 127 controls the rotational speed of the motor 6 so that it reaches the specified rotational speed.

The output of Litori's mono multivibrator lO3 is "1"
The operation time at the level is the printing time of one unit of character code information, for example, in this embodiment, one recording sheet
The printing time T is set to be one page, and the printing time TR is set to be longer (FIG. 2). This set time TR is appropriately set depending on the time required for the code conversion process, the print speed, and the like. Therefore, even if there is idle time in the printer controller 10 during printing when the code conversion process is not completed and bit information is not sent from the character controller 9, the speed is not changed as in the past, but the ridrigger monomultiple The rotation of the specified rotational speed motor 6 is maintained within the set time TR of the vibrator 103.

When the print start command Ss is output again after the print time T, the retry one-mono multivibrator 103 is triggered redundantly to the "1" level output state caused by the previous trigger (see Fig. 2 200). ), a new set time TR is started, and an output signal of "1" level is generated during that period.

A certain period of time (i.e., TR-T
If the print start signal S8 is not output even if s=t) has elapsed, that is, even if the set time TR has elapsed since the print start signal S3, the output voltage of the ridrigger mono multivibrator 103 is at the "0" level. Nashi (
(202) in FIG. 2), as a result, the output voltage of the Jinimpark 123 becomes "1", and the AND gate 124 becomes operable, and conversely, the AND gate 125 becomes inoperable. As a result, only the output signal of the oscillator 121 is transmitted to the PLL circuit 12.
7 and the motor 6 is driven at low speed rotation. The drive by this low speed rotation will be followed by the print start signal S,
This process continues until l is output.

In addition, in the above embodiment, speed switching was performed by a retrigger monomultipibrator, but
In addition, it is also possible to use program control such as a CPU.

Although an embodiment in which the present invention is applied to a printer that outputs data from a host machine has been described, the present invention also includes the following:
It is also advantageously applied to recording systems of copying machines and facsimile machines.

Effects According to the present invention, even if the code conversion process is not completed during the print time, the rotational speed of the motor for driving the polygon mirror is maintained at the specified rotational speed during the predetermined period.
There is no reduction in printout speed due to speed switching, and there is no reduction in print quality. Furthermore, since the frequency of speed switching is reduced, the life of the motor can also be extended.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a scanner control device according to the present invention, FIG. 2 is a timing chart showing signal waveforms appearing in each part in the embodiment of FIG. 1, and FIG. FIG. 4 is a block diagram showing an example of a control device applied to the apparatus shown in FIG. 3. FIG. Explanation of symbols of main parts 1... Semiconductor laser, 3... Rotating polygon mirror, 6...
Motor, 10... Printer controller, 12...
Motor driver, 103... Retrigger monomultipibrator, 121, 122... Oscillator, 124°12
5...AND dart, 126...OR date, 12
7...PLL circuit, 128...driver. Figure 1

Claims (1)

[Scope of Claims] Conversion means for receiving character code information and converting it into corresponding bit information; laser generation means for generating a laser beam modulated in accordance with the bit information; and a polygonal rotating mirror; a scanning means for deflecting and scanning the laser beam by rotating a polygonal rotating mirror; a scanning means for controlling the rotation of the scanning means; a first predetermined rotational speed; and a second predetermined rotational speed faster than the first predetermined rotational speed. A control device for a printer scanner for printing characters representing the bit information, the control device having a control device for selectively rotating the scanning device at a rotational speed, wherein the control device receives a signal instructing printing. and a timer for rotating the polygonal rotating mirror at a second predetermined rotation speed for a predetermined period of time, and the predetermined period is set to be longer than a period for printing characters associated with one unit of character code information. , the control means is
Normally, the polygonal rotating mirror is rotated at a first predetermined rotational speed, and in response to the signal instructing printing, the polygonal rotating mirror is rotated at a second predetermined rotational speed for the predetermined period. A printer scanner control device characterized by: