JP2941873B2 - Image recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus that performs automatic light output control (APC) using a semiconductor laser, a light emitting diode, and the like.

[Conventional technology]

Conventionally, in an image recording apparatus using a semiconductor laser, a light emitting diode, and the like used in a printer, a copying machine, and the like,
Since the light intensity output of a semiconductor laser, a light emitting diode, or the like changes with temperature or aging, a change in density of a recorded image, a change in line width of characters and the like, and a decrease in image quality occur. Therefore, in order to prevent such a decrease in image quality, an image recording apparatus has been put to practical use in which control is performed to keep the light intensity output of a semiconductor laser, a light emitting diode or the like constant.

FIG. 7 shows an example of an automatic light output control (APC) circuit of the image exposure apparatus 3 using a semiconductor laser. Reference numeral 30 denotes a laser diode, 31 denotes a photodiode, 32 denotes a constant current circuit for controlling the amount of current for causing the laser diode 30 to emit light, and 33 denotes a switching circuit thereof. The switching circuit 33 determines whether or not the current determined by the constant current circuit 32 is allowed to flow to the laser diode 30 according to an image signal input from the outside.

The photodiode 31 is connected to an amplifier 34, and the output voltage of the amplifier 34 is compared with the output voltage of a reference voltage generator 36 by a comparator 35. The output of the comparator 35 is connected to the constant current circuit 32.

The comparator 35 feeds back the comparison result between the signal of the photodiode 31 corresponding to the light output of the laser diode 30 and the output voltage of the reference voltage generator 36 to the constant current circuit 32, and the light output intensity of the laser diode 30 is increased. It is controlled to be constant.

FIG. 2 shows an example of a laser beam printer using such an image exposure device 3.

The photosensitive drum 1 rotates in the direction of the arrow, and is uniformly negatively charged by the charging roller 2 to which a high voltage is applied. A latent image is formed on the photosensitive drum 1 by irradiating a laser beam by the image exposure device 3 (image exposure), and the latent image is visualized by negatively charged toner in the developing device 4. After the visualized toner image is transferred onto the transfer material P by the transfer roller 5,
The image is fixed by the fixing device 6. The residual toner on the photosensitive drum 1 is removed by the cleaning device 7.

The image exposure apparatus 3 performs APC during a period called pre-rotation prior to the exposure of the first page and between sheets. During the APC period, light emitted from the semiconductor laser 30 in the image exposure apparatus 3 travels on the photosensitive drum 1. Since the scanning is performed, a latent image is formed on the photosensitive drum 1 during the APC period.
When developed, the unnecessary toner adheres to the photosensitive drum 1, and as a result, a problem such as toner contamination of the transfer roller 5 occurs. Then, the stain on the transfer roller 5 causes back stain on the transfer material P. If a transfer bias is applied when the latent image passes through the transfer portion, a memory is generated on the photosensitive drum 1 corresponding to the latent image. This memory appears as charging potential unevenness at the next charging, and is developed to cause fogging on the image.

Therefore, an unblanking APC in which the APC exposure is performed only outside the image area on the side of the image has been proposed.

 FIG. 8 shows an unblanking APC circuit diagram.

30 is a laser diode, 31 is a photodiode, 32
Is a constant current circuit for controlling the amount of current for causing the laser diode 30 to emit light, and 33 is its switching circuit.

The switching circuit 33 determines whether or not the current determined by the constant current circuit 32 is allowed to flow to the laser diode 30 based on an externally input image signal.

The UNBL signal is a laser forcible lighting signal for generating a horizontal synchronization signal (referred to as BD) necessary for synchronization in the main scanning direction in order to synchronize images in a laser beam printer having a laser scanning optical system.

When BD is turned on by the UNBL signal, the constant current circuit 32
The current determined by the switching circuit 33 flows to the laser diode 30 by the switching circuit 33.

At the same time, the up-down counter 37 outputs the UNBL signal.
Because it is True, it is in the count state.

A photodiode 31 for detecting the light output intensity of the laser diode 30 feeds back a detection voltage to a comparator 35 via an amplifier 34. The comparator 35 compares this voltage with the reference voltage generated by the reference voltage generator 36.

If the output voltage of the amplifier 34 has not reached the reference voltage, the output of the comparator 35 indicates a count-up, and the up-down counter 37 counts up the D / A converter 38 and outputs a constant current through the buffer 39. The circuit 32 boosts the current flowing through the laser diode 30.

When the diode 30 emits light by the above operation, the UNBL signal becomes
It becomes the BD cycle, and becomes True only in the area outside the photoconductor, and the APC exposure is performed only in the area outside the photoconductor.

If the output voltage of the amplifier 34 is higher than the reference voltage,
The output of the comparison unit 35 has a logic opposite to that of the above case, the count of the counter 37 is reduced, and the laser diode 30
The current to is reduced.

As described above, if the CLK cycle of the up-down counter 37 is longer than the response time of the feedback circuit, the unblanking APC can correct the current of the laser diode 30 with the minimum bit for each scanning line. .

[Problems to be solved by the invention]

However, the above conventional example has the following two disadvantages.

1) In the unblanking APC, APC cannot be performed until the scanning mechanism of the laser scanning optical system enters a steady state, and the amount of change in current to the laser diode 30 is extremely small every BD cycle. For this reason, when the power of the laser beam printer is turned on, or when the laser beam printer is left for a long period of time after power-on, the laser diode
When the amount of correction of the current to 30 is large, many UNBL signals must be input before the current reaches the target value, and it takes a long time, so that the wait time of the laser beam printer and the First print time becomes longer.

2) An image of solid black or a substantially uniform density (for example, main scan 1)
When the laser diode 30 is driven at a constant current within a page for a line print, a repetitive image in which one line is paused, or a substantially uniform halftone image using a pulse width modulation drive method for an image signal, the laser diode 30 is used. Since the light output intensity changes continuously, unevenness on the image is hardly noticeable. On the other hand, if unblanking APC is performed on a similar image even in a page, the light output intensity changes discontinuously before and after scanning in which the correction of the current of the laser diode 30 occurs, and a sharp change appears in the image density. So, visually,
Extremely noticeable unevenness occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to adjust the amount of light before image recording at high speed without soiling the paper and to shorten the time until image recording starts.

[Means for solving the problem]

An image forming apparatus according to the present invention includes: an emission unit that emits a light beam; an exposure control unit that forms a latent image on the photoconductor by scanning the light beam emitted from the emission unit onto the photoconductor; Developing means for visualizing the latent image by attaching toner to a portion where the light beam is exposed by the exposure control means; and a toner image visualized by the developing means on a transfer material by a contact transfer method. Transferring means for transferring, detecting means for detecting the light output intensity of the light beam emitted from the emitting means, and controlling the drive current of the emitting means based on the light output intensity of the light beam detected by the detecting means A light quantity control means for controlling a light output intensity of a light beam generated from the emission means to a reference value, and a light quantity control means for controlling a light quantity by the light quantity control means. The developing bias of the developing unit is controlled to be off during a first period in which at least a region including the exposed region passes so that the exposed region exposed by the irradiated light beam is not developed, and during the first period, When the developing bias is turned off, the toner of the opposite polarity that adheres to an area other than the exposure area and then adheres to the transfer unit is transferred to the photoconductor after the first period elapses. During the period, the transfer bias of the transfer unit is controlled to be ON, and the second period is a time required for the toner of the opposite polarity attached to the transfer unit to be transferred onto the photoconductor, The image recording is started after the lapse of the second period.

FIG. 1 is a block diagram showing a configuration of an automatic optical output control circuit in an image recording apparatus according to a first embodiment of the present invention.

30 is a laser diode, 31 is a photodiode, 32
Is a constant current circuit for controlling the amount of current for causing the laser diode 30 to emit light, and 33 is its switching circuit.

The switching circuit 33 determines whether or not the current determined by the constant current circuit 32 is allowed to flow to the laser diode 30 according to an image signal input from the outside.

When the power of the laser beam printer as the image recording device of the present invention is turned on or during pre-rotation, the PRL signal, which is a signal for turning on the laser intensely regardless of image synchronization, is set to True, and the laser diode 30 is turned on continuously. .

At the same time, the up-down counter 37 enters the count state because the PRL signal is True.

The photodiode 31 detects the light emitted from the laser diode 30 and feeds it back to the comparator 35 via the amplifier 34. The comparator 35 compares the output voltage of the amplifier 34 with the reference voltage generated by the reference voltage generator 36. Amplifier 34
If the output voltage of the
The output of 35 indicates the count-up of the up-down counter 37, and the output value to the D / A converter 38 is counted up. The output of the D / A converter 38 is supplied to a constant current circuit 32 via a buffer 39, whereby the current flowing through the laser diode 30 is increased.

When the output voltage of the amplifier 34 reaches the reference voltage,
The PRL signal is set to false, and the counter 37 is held. At this time, the laser diode 30 is driven at a constant current with the held current value, and image exposure of the first page is performed.

After the image exposure of the first page is completed and the timing of the paper interval until the image exposure of the second page is started, the laser intermission UNBL signal serving as the laser forcible lighting signal and the start signal of the counter 37 is set to True outside the image area.

The photodiode 31 detects the light output intensity of the laser diode 30 and feeds back the detected voltage to the comparator 35 via the amplifier 34. The comparator 35 compares the output voltage of the amplifier 34 with the reference voltage generated by the reference voltage generator 36.

If the output voltage of the amplifier 34 has not reached the reference voltage,
The output of the comparator 35 indicates the count up, and the up-down counter 37 counts up the output value to the D / A converter 38. The output of the D / A converter 38 is supplied to a constant current circuit 32 via a buffer 39, whereby the current flowing through the laser diode 30 is increased.

When the output voltage of the amplifier 34 is higher than the reference voltage,
The output of the comparator 35 has the opposite logic to that of the above case, the count of the counter 37 is reduced, and the laser diode 30
The current to is reduced.

As described above, if the CLK cycle of the up-down counter 37 is longer than the response time of the feedback circuit, the amplifier ranking APC corrects the current of the laser diode 30 with the minimum bit for each scanning line.

If the correction of the light output intensity is completed, the paper interval UNBL signal is false.
Then, the counter 37 is set to the hold state, and the laser diode 30 is driven at a constant current to perform image exposure of the second page with the held current value.

The inter-sheet unblanking APC is performed on the second and subsequent pages in the same manner as the first and second pages.
Corrects fluctuations in light output intensity due to a rise in laser temperature during continuous use.

Specifically, an example in which the image exposure apparatus of FIG. 1 is used as an image exposure apparatus 3 of a laser beam printer as shown in FIG. 2 will be described.

In FIG. 2, when the pre-rotation operation is started, the Al
The photosensitive drum 1 having the cylinder coated with the OPC photosensitive member is rotated at a process speed of 47 mm / sec, and is uniformly negatively charged to -600 V by the charging roller 2. As the charging roller 2, a conductive elastic body is used.

During the pre-rotation operation, the image exposure device 3 controls the AP by continuous lighting.
C, the light of the laser diode 30 scans the photosensitive drum 1 so that a latent image is formed on the photosensitive drum 1. When the latent image is developed by the negatively charged toner of the developing device 4, the photosensitive drum Unnecessary toner adheres to the transfer roller 1, and as a result, the transfer roller 5 is stained. However, at the time of the pre-rotation, the problem can be easily solved in the following point as compared with the sheet interval.

The toner stain on the transfer roller 5 does not adhere to the back surface of the transfer material if a bias of a polarity (negative) at which the toner on the transfer roller 5 transfers to the photosensitive drum 1 is applied to the transfer roller 5. However, in the case of continuous lighting APC between the sheets, when the attached toner is to be transferred to the photosensitive drum 1, the throughput is extremely reduced. If the toner is not transferred to the photosensitive drum 1, the toner appears as a stain on the back surface of the next transfer material. On the other hand, when the continuous lighting APC is performed during the pre-rotation, the throughput attached to the transfer roller 5 is not deteriorated even if the toner attached to the transfer roller 5 is transferred to the photosensitive drum 1, and the surface of the transfer roller 5 must be sufficiently cleaned. Can be.

The operation time chart in such a case is shown in FIG.

Alternatively, the operation may be performed as shown in FIG. In this case, for the latent image formed by the continuous lighting APC,
When the developing bias is turned off and the sheet passes through the transfer portion without developing, if a positive transfer bias is applied, a memory is generated on the photoconductor corresponding to the latent image.

When the transfer bias is set to a negative value so as not to generate a memory, when the developing bias is turned off for the latent image formed by the continuous lighting APC, the developing bias is turned off, and the non-exposed portion of the photosensitive drum 1 has the opposite polarity (positive polarity). ), The toner is transferred onto the transfer roller 5. Attempting to clean the toner between the sheets causes a decrease in throughput. However, during the pre-rotation, it is necessary to apply a positive bias at the timing when the toner adhering portion on the transfer roller 5 faces the photosensitive drum 1. Accordingly, the transfer roller 5 can be cleaned in the period W1.

In the example described above, the charging of the photosensitive drum 1 was started at the start of the pre-rotation, but the charging was not started at the time of the pre-rotation.
Continuous lighting APC may be performed in the non-charging portion of the photosensitive drum 1 and charging may be started after APC is completed. In this case, the above-described problem does not occur, and the pre-rotation time increases by 0.3 at most. There is no problem at about msec.

As described above, the continuous lighting APC during the pre-rotation can be executed without any problem.

When the driving current of the laser diode 30 for obtaining the target light output intensity is held by the continuous rotation APC during the pre-rotation, a laser beam image-modulated to 300 dpi by the image exposure device 3 is projected on the charged surface by the image exposure device 3, The potential at that portion is attenuated to form an electrostatic latent image.

When this electrostatic latent image arrives at a developing site of the developing device 4 facing the photosensitive drum 1, negatively charged toner is supplied from the developing device 4 and adheres to the latent image site to form a toner image. During the image exposure period, the laser diode 30 is driven at a constant current, so that rapid density unevenness does not occur during development.

Further, when the photosensitive drum 1 rotates and the toner image reaches a transfer portion, which is a press-contact nip portion between the photosensitive drum 1 and the φ20 transfer roller 5 that presses against the photosensitive drum 1, the transfer material P is synchronized with the transfer.
Is conveyed to the transfer portion, and at the same time, a positive transfer bias is applied to the transfer roller 5, and the toner image on the photosensitive drum 1 is transferred to the transfer material.

Thereafter, the transfer material P is separated from the photosensitive drum 1 and the toner image is fixed on the transfer material P by the fixing device 6, while the toner remaining on the photosensitive drum 1 is removed by the cleaner 7, and the photosensitive drum 1 Of the image forming process.

Generally, chloroprene rubber,
Disperse carbon, etc. in NBR, urethane rubber, silicon rubber, EPDM, etc., and have a volume resistance of 10 ⁵ to 10 ¹¹ Ωcm and a hardness of 20
A roller adjusted to a hardness of about 30 mm (Asker C hardness) may be used alone, or the surface of this roller may be coated with polyvinylidene fluoride, polyester-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, or polystyrene-based thermoplastic. Plastic elastomer,
A two-layer structure is formed by coating a polyamide thermoplastic elastomer, a fluorine-based thermoplastic elastomer, an ethylene-vinyl acetate-based thermoplastic elastomer, a polyvinyl chloride-based thermoplastic elastomer, and the like to form a two-layer structure. Adjust the resistance of the elastomer by mixing a conductive filer such as, or a semi-conductive filer such as a titanium compound, a nickel compound silicon compound, or changing the structure of the polymer itself,
The volume resistance of the elastomer layer is adjusted between 10 ^{11 and} 10 ¹⁵ Ωcm.

 The image exposure device 3 will be described in more detail.

In FIG. 1, the laser diode 30 and the photodiode 31 of 5 mW use an integrated laser unit of φ9 package, and the reference voltage generator 36 is a circuit supply voltage.
Vcc was divided by a variable resistor. 3
As 8, a 12-bit D / A converter was used.

Since the emission field pattern of the laser diode 30 varies from one laser diode to another, the efficiency of transmission through the collimator lens for collimating the divergent light from the laser diode 30 of the optical system of the image exposure device 3 varies. In order to obtain a desired light amount on one surface, the light output intensity on the chip surface of the laser diode 30 varied from about 1.5 to 4.0 mW depending on the individual.

When the unblanking APC is used instead of the continuous lighting APC as in the present embodiment as the APC at the time of the pre-rotation, it takes a maximum of 1.5 seconds or more to reach the target light output,
By using the continuous lighting APC at the time of the pre-rotation as in the present invention, it was possible to complete the operation within a maximum of 250 msec.

Unblanking APC exposure between papers was performed for a period of about 150 μsec for every BD cycle of about 1.8 msec. The unblanking APC between papers could be completed in one to several lines of main scanning.

According to the present embodiment of the present invention, it is possible to provide an image recording apparatus having an image exposure apparatus that performs an unblanking APC, has a short wait time and a fast print time, and does not cause sharp density unevenness in a page.

Next, as another embodiment of the present invention, in a laser beam printer using an image exposing device 3 having an automatic light output control mechanism similar to that described in the above-described embodiment, a transfer roller The case where the transfer roller 3 is prevented from being stained and the transfer roller 3 is cleaned by applying a polarity bias will be described.

The laser beam printer is similar to that shown in FIG.

FIG. 5 shows a sequence diagram of the present embodiment. This will be described with reference to FIG.

The photosensitive drum 1 is rotated at a process speed of 47 mm / sec by a main motor or the like, and the printer is set to a pre-rotation operation which is a preparation rotation for printing. Continuous lighting APC is performed during the pre-rotation, and the light output intensity of the laser diode 30 is set as a target value. When the continuous lighting APC is completed, a charging bias in which a DC bias of -600 V and an AC bias of 1600 Vp-p are superimposed on the charging roller 2 is applied to charge the photosensitive drum 1 to -600 V. Next, a DC bias of -450 V was applied to the developer carrying member of the developing device 4 having the negatively charged toner for 1800 hours.
A developing bias on which an AC bias of 1600 Vp-p at Hz is superimposed is applied. Transfer roller 5 similar to that shown in the first embodiment
And a positive transfer bias of +1.5 kV is applied.

When the printing of the first page is started, the laser diode 30 is driven at a constant current at the constant current value determined at the time of the pre-rotation to perform image exposure. The surface potential of the exposed photosensitive drum 1 is attenuated to -150 V, developed by the toner of the developing device 4, and transferred onto the transfer material P by the transfer roller 5.

When the printing of the first page is completed and the paper interval is reached, the image exposure device 3 performs the same unblanking APC as shown in the first embodiment, and corrects the light output intensity of the laser diode 30.

On the other hand, a negative transfer bias of −2 kV is applied to the transfer roller 5 between the sheets. At this time, the surface of the photosensitive drum 1 is -600V
The negatively charged toner adhering to the surface of the transfer roller 5 is transferred from the surface of the transfer roller 5 to the surface of the photosensitive drum 1, and the surface of the transfer roller 5 is cleaned.
Since the unblanking APC is performed between sheets, the transfer roller 5 scrapes the developing toner on the photosensitive drum 1 when the continuous light APC is performed, so that the surface of the transfer roller 5 is not stained. Further, since the surface potential of the photosensitive drum 1 at the time of cleaning the transfer roller between sheets is uniform, the surface of the transfer roller 5 can be uniformly cleaned.

The negative transfer bias has a higher cleaning effect on the surface of the transfer roller 5 as the potential difference from the surface potential of the photosensitive drum 1 is larger, but it is necessary that the negative transfer bias does not cause dielectric breakdown of the photoconductor. According to the study of the present inventor, when the negative transfer bias was set to −4 kV, dielectric breakdown of the photoconductor occurred, so that
It is preferable that the negative transfer bias is -3.5 kV or less.

When printing the second page, blanking between the sheets
With the constant current value determined by the APC, the laser diode 30 is driven at a constant current to perform image exposure. At this time, a negative transfer bias is applied.

When the printing of the second page is completed, the laser beam printer enters post-rotation, turns off the charging bias, the developing bias, and the positive transfer bias, and stops.

According to this embodiment, the effects of shortening the fast print time and preventing sharp unevenness of the image shown in the above-described embodiment are achieved, and the transfer roller 5 is prevented from being stained. The toner contamination on the back of the material P is prevented. Further, since the cleaning of the transfer roller 5 is performed between sheets, the cleaning time of the transfer roller 5 at the time of pre-rotation and post-rotation can be short. As a result, the pre-rotation time and post-rotation time can be shortened, the printing time can be shortened, and the photoreceptor shaving accompanying the rotation of the photosensitive drum 1 can be reduced, particularly in the cleaning section.
It also has the effect of extending the life of the photoconductor.

[Second Embodiment] In the present embodiment, the size of the transfer material in the image scanning width direction is detected, and the light emission time during the inter-sheet blanking APC is switched.

 This embodiment will be described with reference to FIG.

Reference numeral 1 denotes a photoconductor, reference numeral 30 denotes a semiconductor laser light source,
80 is a collimator lens, 81 is a polygon mirror for scanning the laser beam, 82 is an imaging lens for narrowing the laser beam to a predetermined beam diameter, 83 is a part of the laser beam incident on a laser beam detector 84 Reflector for the
Reference numeral 85 denotes a position at which a signal for controlling the image signal is sent to the image signal control circuit, and S (shaded area) is an area where the laser beam sweeps.

Prior to image recording, the image recording apparatus according to the present embodiment detects the size of the transfer material in the image scanning width direction using a sheet cassette capable of recognizing the size of the transfer material, a transfer material width detection sensor, or the like.

At the time of pre-rotation prior to the image recording of the first page, continuous lighting APC is performed, and the laser diode 30 is driven at a constant current,
The image of the first page is exposed. In the space between the first and second pages, APC is performed at a position corresponding to the image area of the transfer material according to the detected transfer material size, and the drive current of the laser diode 30 is corrected.

For example, in FIG. 6, in the case of the transfer material size of 86, APC is performed in the area indicated by 87, and in the case of the transfer material size of 88, APC is performed in the area indicated by 89.

Thus, in the case of a small-size transfer material, the laser diode 3 in one light emission of the inter-sheet blanking APC is used.
By increasing the correction amount of the light output intensity of 0, it is possible to reduce the number of light emission scans in the sheet blanking APC.

In the case of a small-sized transfer material, a memory of the photosensitive drum 1 is generated when a transfer bias is applied to an inter-sheet blanking APC exposure unit. Absent.

Contamination of the transfer roller 5 when the exposed portion is developed does not substantially cause a problem in this embodiment because the number of APC scans is small in this embodiment, but it is preferable that toner is transferred to the transfer roller 5 to the photosensitive drum 1. Bias or
The toner on the surface of the transfer roller 5 is preferably removed by mechanically rubbing the surface of the transfer roller 5.

〔The invention's effect〕

According to the present invention, an emission unit that emits a light beam, an exposure control unit that forms a latent image on the photoconductor by scanning the light beam emitted from the emission unit onto a photoconductor, and the exposure unit Developing means for visualizing the latent image by attaching toner to a portion exposed to the light beam by the control means; and transferring the toner image visualized by the developing means to a transfer material by a contact transfer method Transfer means,
Detecting means for detecting the light output intensity of the light beam emitted from the emission means, and controlling the drive current of the emission means based on the light output intensity of the light beam detected by the detection means, Light amount control means for performing light amount control for controlling the light output intensity of the light beam generated from the means to a reference value, and an exposure area exposed by the light beam emitted during the light amount control by the light amount control means. The developing bias of the developing unit is controlled to be turned off during a first period in which at least the region including the exposure region passes, so that the developing bias is turned off during the first period. The opposite polarity toner adhered to the area other than the exposure area and then adhered to the transfer means,
The transfer bias of the transfer unit is controlled to be on during a second period so as to transfer onto the photoreceptor after the first period has elapsed, and the opposite polarity adhered to the transfer unit is controlled during the second period. This is the time required for the toner to be transferred onto the photoconductor, and by starting the image recording after the elapse of the second period, the light amount adjustment before the image recording can be performed without soiling the transfer material. Since the processing can be executed not only in the image area but also in the image area, the time until the start of image recording can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an automatic light output control circuit in an image recording apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view of the image recording apparatus, and FIGS. FIG. 6 is a diagram for explaining an operation in the second embodiment, and FIGS. 7 and 8 are configuration diagrams of a conventional automatic optical output control circuit. FIG. 3. Image exposure device 30 Laser diode 31 Photo diode 32 Constant current circuit 33 Switching circuit 35 Comparator 36 Reference voltage generation circuit 37 Up-down counter 38 D / A converter

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 2/44 G03G 15/16 G03G 21/00 H04N 1/04

Claims (4)

(57) [Claims] An emission unit for emitting a light beam; an exposure control unit for forming a latent image on the photosensitive member by scanning the light beam emitted from the emission unit on the photosensitive member; Developing means for visualizing the latent image by attaching toner to a portion exposed to the light beam by means, and transfer for transferring the toner image visualized by the developing means to a transfer material by a contact transfer method Means, detecting means for detecting the light output intensity of the light beam emitted by the emitting means, and controlling the drive current of the emitting means based on the light output intensity of the light beam detected by the detecting means. A light amount control unit that performs light amount control for controlling a light output intensity of a light beam generated from the emission unit to a reference value, and the light amount is emitted when the light amount control unit controls the light amount. A developing bias of the developing unit is controlled to be off during a first period in which at least a region including the exposed region passes so that an exposed region exposed by the light beam is not developed, and a developing bias is controlled during the first period. Is turned off so that toner of the opposite polarity that adheres to an area other than the exposure area and then adheres to the transfer unit is transferred to the photoconductor after the first period has elapsed. And controlling the transfer bias of the transfer unit to be on. The second period is a time required for the opposite polarity toner adhered to the transfer unit to be transferred onto the photoconductor, and 2. An image recording apparatus, which starts image recording after a lapse of a period of 2. 2. An image recording apparatus according to claim 1, wherein said toner is transferred onto said photosensitive member by applying a predetermined bias to said transfer means. 3. An image according to claim 2, wherein said toner is transferred onto said photosensitive member by applying a bias having the same polarity as that of the toner attached to said transfer means to said transfer means. Recording device. 4. When performing image recording of a plurality of pages, it is preferable that the light emission control is executed by forcibly driving the ejecting means in a non-image area corresponding to a size of a transfer material between sheets. The image recording apparatus according to claim 1, wherein: