JPS62109078A - Image recorder - Google Patents

Abstract

PURPOSE:To permit the continuous outputting of images having always stable density by calculating the consumption of a developer according to input image information and replenishing the developer conforming thereto to a developing means in parallel with the development. CONSTITUTION:An exposing device 3 is constituted of an LED array 3a and an optical convergent lens array 3b, etc. A developing device 4 is constituted of a developing roller 4a and an agitating roller 4b. A replenishing device 5 is constituted of a toner container (hopper) 5b for replenishing the developer (toner) and a replenishing roller 5a for replenishing the toner. A transfer device 7 transfers the toner image formed on a photosensitive body 1 by, for example, corona discharge., etc., onto transfer paper P. A replenishing control part 17 constituting a replenishing control means transmits the pulse signal corresponding to the number of pulses TN latched in a latch 16b in synchronization with a development start signal DS to a replenishing motor 18 to drive the replenishing roller 5a of the replenishing device 5, thereby replenishing the toner conforming to the consumption of the developer from the hopper 5b. The control part 17 is constituted of a pulse oscillator, down counter, motor driver, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording device that visualizes a latent image formed by electrophotography as a toner image.

[Conventional technology]

Conventionally, the developing methods of the developing means used in this type of device include a two-component developing method that uses a mixture of polyester resin toner and iron powder, and an l-component developing method that uses only polyester resin toner. There is.

Among these, in the two-component development method, the toner concentration in the developer fluctuates due to a decrease in toner in the developer due to a developing operation or an increase in toner due to toner replenishment.

If the toner density is low, the image density on the recording material (recording paper) will be low, leading to blurring or even image disappearance, and if the toner density is high, fogging will occur in non-image areas. In order to overcome this, the following (1), (
A method of controlling the toner concentration in the developer using the method shown in 2) has been proposed and implemented.

(1) A method of replenishing a predetermined amount of toner when the rotational speed of the photoreceptor during image formation reaches a predetermined rotation speed.

(2) When the toner concentration in the developer in the developing device is directly detected and the detection signal falls below a predetermined level.

How to perform a predetermined amount of toner replenishment.

[Problem that the invention seeks to solve]

However, in method (1) above, regardless of the type of recorded image (blackening rate), the toner density may be over or under due to constant replenishment, resulting in the recorded image being too light or too dark, resulting in poor image output. Not stable.

In addition, in method (2), the toner concentration in the developer is directly detected, so replenishment control is easy, but it is difficult to detect with high precision, and the toner does not reach a certain level F. It will not be replenished and will only be replenished once it reaches that level or below. This causes the toner concentration in the developer to change drastically, and when the same image is printed continuously, the density of the first output image and the subsequent output image differs, resulting in a light image and a dark image. It will be output. Furthermore, since human color vision is particularly sensitive, unless the density of each toner can be kept constant with high precision, a multi-color (two or three or more monochromatic colors) or full-color printers with multiple developing devices will not work properly. Variations in the density of each toner not only make it difficult to reproduce faithful colors, but also cause problems such as differences in color development between recorded images during continuous printing. There were some issues.

This invention has been made to solve the above problems, and provides an image recording device that can continuously output images with stable density by replenishing the developer consumed during latent image formation. The purpose is to

[Failure to solve the problem]

The image recording apparatus according to the present invention includes a consumption amount calculation means for calculating the consumption amount of developer according to input image information, and a developer corresponding to the developer consumption amount calculated by the consumption amount calculation means. A replenishment control means is provided for replenishing the developing means in parallel with the development of the means.

[Effect]

In this invention, the replenishment control means supplies the developer from the replenishment means to the developing means in parallel with the development of the electrostatic latent image formed on the photoreceptor, in an amount corresponding to the amount of developer consumed calculated by the consumption amount calculation means. Replenish.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an image recording apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a photoreceptor having a photoconductive layer on one surface, and rotates in the direction of the arrow. A charger 2 charges the photoreceptor 1 uniformly. Reference numeral 3 denotes an exposure device, which includes an LED array 3a, a light converging lens array 3b, and the like.

4 is a developing device, which includes a developing roller 4a and a stirring roller 4b.
It consists of Reference numeral 5 denotes a replenishing device, which includes a toner storage container (hopper) 5b for replenishing developer (toner) and a replenishment roller 5a for replenishing toner. 6 is a paper feed cassette in which transfer paper P is accommodated. A transfer device 7 transfers a toner image formed on the photoreceptor 1 to a transfer paper P by, for example, corona discharge. 8 is a cleaning device, which is composed of a blade, a cleaning roller, etc., and a photoreceptor]
Collect residual toner. A conveying device 9 conveys the transfer paper P to the fixing device 1o. Reference numeral 11 denotes a paper discharge tray, on which the transfer paper P that has been heat-pressed and fixed by the fixing device 10 is placed.

Reference numeral 12 denotes a reader section, which outputs an image signal Vo (0, 1) obtained by photoelectrically converting the reflected light of the document obtained by optical scanning to an AND circuit 13.
Send to one terminal of The other side of the AND circuit 13 has
A scan signal S indicating the scan state of the reader section 12 is input. The scan signal S is "O" when the league unit 12 calculates the toner consumption amount during pre-scanning
'', and is a signal that becomes ``rl'' during image formation. 14
is a driver circuit that sends out a drive signal to drive the LED array 3a of the exposure device 3 in accordance with the output of the AND circuit 13. A counter section 15 counts "1" (printed dots) of the image signal Vo sent out from the league section 12. The counter section 15 is composed of, for example, an UP counter. 16 is a toner consumption calculation circuit, and pulse number output section 1
6a and a latch 6b that holds the number of pulses TN output by the pulse number output section 16a. The pulse number output section 16a outputs the output of the counter section 15 (count value T
) The number of pulses TN addressed according to the latch 16b
Send to. The latch 16b is a briscan end signal P.
The pulse aTs sent out from the pulse number output section 16a in synchronization with [ is latched. Reference numeral 17 denotes a replenishment control section which constitutes replenishment control means of the present invention, and receives the input development start signal Ds.
The number of pulses TN latched by the latch 16b in synchronization with
A pulse signal corresponding to the amount of developer consumed is sent to the replenishment motor 18, and the replenishment roller 5a of the replenishment device 5 is driven to replenish toner from the hopper 5b in accordance with the amount of developer consumed. The replenishment control section 17 is composed of a pulse oscillator, a down counter, a motor driver, and the like.

Next, the operation of FIG. 1 will be explained with reference to FIGS. 2(a) to 2(f).

FIGS. 2(a) to 2(f) are timing charts explaining the operation of FIG. 1.

The same figure (a) shows the scan timing of the league part 12, the same figure (b) shows the calculation timing of the number of pulses TN,
(c) of the same figure shows the development timing of the development device 4, and (j
) shows the drive timing of the supply roller 5a, (e) shows the pre-scan end signal PE, and (f) shows the development start signal Ds.

First, the league unit 12 prescans the document (as shown in FIG. 2(a)) for toner replenishment control, which will be described later, to obtain an image signal vD. At this time, the AND circuit 13 has r
Since the QJ scan signal S is input, the driver circuit 14 does not operate and latent image formation is not performed.

The counter section 15 counts the number of printed dots of the image signal Vo, and sends the count value T to the toner consumption calculation circuit 16. Here, the pulse number output section 16a outputs the stored pulse % T by using the transmitted currant direct T as an address.
Latch Jl+6b is prescan end signal PE
(See FIG. 2(e)). In addition,
The counter section 15 is cleared by the signal QC output from the latch 16b in synchronization with the prescan end signal P[.

Latched pulse e! ; Since ITs is calculated from the total number of dots, it corresponds to the amount of toner consumed to form the image that is about to be output.6 As is well known, the number of dots and toner consumption There is a proportional relationship between the toner consumption amount and the toner consumption amount, and it is easy to calculate the toner consumption amount from the drum. The number of pulses TN latched in the latch 16b is transmitted to the next stage replenishment control section]7.

On the other hand, when the main scan (reading for image output) is performed (t=tz), the scan signal S with the content "l" is input to the AND circuit 13, and the next stage driver circuit 14 outputs the signal from the league section 12. The LED array 3a of the exposure device 3 is selectively activated by the image signal VD, and a dot-shaped electrostatic latent image is formed on the photoreceptor 1 via the light converging lens array 3b. After a predetermined Δ has elapsed from t2, t3
The developing device 4 is driven in synchronization with the development start signal Ds sent out at , and the replenishment control section 17 also drives the pulse T in synchronization with the development start signal Ds (section signal).
A pulse signal of H is sent to the replenishment motor 18, and the replenishment device 5
The replenishment roller 5a is driven to replenish toner from the hopper 5b in an amount corresponding to the amount of developer consumed. In addition, Fig. 2 (a) ~
The image formation shown in (f) shows the case where the same image is formed three times in a row, and each image formation is performed by replenishing toner for three sheets according to the number of printed dots read in one pre-scan. Do this in parallel.

It goes without saying that by gradually replenishing toner during development, for example while the stirring roller 4b is rotating, it is possible to suppress fluctuations in toner concentration due to toner replenishment.

Further, in the first embodiment, a monochrome printer has been described, but the invention is not limited to this, and the present invention can also be applied to a color printer. For example, the amount of toner consumed for each color may be calculated from an image signal separated into a plurality of colors, and toner replenishment for each color may be performed in synchronization with the development timing of each color. A case in which the present invention is applied to a color printer will be described below.

FIG. 3 is a sectional view schematically showing a full-color image recording system according to another embodiment of the present invention, which can be roughly divided into an upper color image reading device 21 (hereinafter referred to as a blade color reader) and a portion of a color image recording device 22 ( It consists of a color printer (hereinafter referred to as a color printer).

First, the configuration of the color reader 21 will be explained.

A document 23 is placed at a predetermined position on a document table 24 . 2
A scanning unit 5 optically reads the original 23. The scanning unit 25 includes a rod array lens 25a, a 1-1 magnification type color separation line sensor 25b (hereinafter referred to as a "blade color sensor"), an exposure lamp 25c, and the like. A flexible cord 26 transfers the output of the color sensor 25b to the image processing section 27.

The scanning unit 25 reads the image (main scan) when scanning in the direction of arrow A from the left position in this figure, and is located on the right side (indicated by a dotted line) during standby, and issues a print start command (operation unit (not shown)). command), the scanner scans in the direction of arrow B and reaches the main scan start position (back scan). Note that images can be read in both main scan and back scan.

Next, the configuration of the color printer 22 will be explained. Components that are the same as those in FIG. 1 are given the same reference numerals.

31y, 31M, 31G, 318 are developing units, and toner hoppers 32y, 32m, 32c.
, 32ex to supply rollers 33Y, 33M,
Each yellow toner T is driven by 33c and 338.
Y, magenta toner TM, cyan toner Tc, and black toner T8 are replenished. Reference numeral 34 denotes a transfer section, which includes a gripper 34a that grips the transfer paper P, and a transfer drum 34b.
, a transfer charger 34c. A peeling claw 35 separates the transfer paper P on which transfer has been completed from the transfer drum 34b.

Next, the operation shown in FIG. 3 will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a schematic diagram illustrating the color sensor 25b shown in FIG. 3, and 41 is a photoelectric conversion element composed of, for example, COD, and one pixel (82,51 Lm square) is divided into about three on its upper surface. Color separation filters of blue filter B, green filter G, and red filter R are attached. Note that the reading scanning direction of the original 23 is the direction of the arrow.

FIG. 5 is a control block diagram of the full-color image recording system shown in FIG. 3, and the same parts as in FIGS. 1 and 3 are given the same reference numerals.

51 is the first selector, which receives the backscan start signal B.
Color digital signals Y, M, C, and BK sent from the image processing section 27 in synchronization with SS are sent to the counter section 15. A second selector 52 stores color digital signals Y, M, C, and BK of predetermined lines in the synchronous memory 53 in synchronization with the main scan start signal Rss. A synchronous memory controller 54 synchronizes with the color printer 22 and sends the color digital signal Y stored in the synchronous memory 53 to the driver circuit 14. A third selector 55 selects one of the replenishment motor drivers 56y, 56s, 56c, and 56flK in synchronization with the development operation signal DS. 57y, 57M, 57c,
A replenishment motor 57e replenishes the developer to be consumed in accordance with the pulse signal of the pulse Ts sent from the replenishment control section 17.

Next, the operation in FIG. 5 will be explained with reference to FIGS. 6(a) to 6(g).

6(a) to 6(g) are timing charts explaining the operation of FIG. 5, in which FIG. 6(a) shows the scanning operation of the color reader 21, FIG. 6(b) shows the developing operation, 4C shows the replenishment operation, FIG. 1D shows the backscan start signal BSS, and FIG. , (f) in the same figure shows the toner amount calculation timing, and (g) in the same figure shows the development start signal Ds. Note that FIG. 1 shows only the replenishment operation when forming one color image.

When a print command is given, the scanning unit 25 shown in FIG. 3 backscans in the direction of arrow B, the exposure lamp 25c is turned on, and reading of the original 23 is started. Then, analog color separation signals AB, AG, and AR are output from the color sensor 25b shown in FIG.
The image processing unit 27 performs predetermined processing (for example, Log conversion, A
/D conversion.

Masking processing, blank plate generation processing) are performed, and the outputs thereof become digital signals Y, M, C, and BK. These digital signals Y, M, C, and BK are the basic data of each toner to be finally printed by the color printer 22. The digital signals Y, M, C, BK of the image processing section 27 are sent to the first selector 52, and the backscan start signal BSS is sent to the first selector 52.
An image signal of one color is selected and transferred to the next stage. For example, if a toner image is formed in the order of yellow, yellow, cyan, and black, the digital signal Y for yellow is selected in the first backscan, and the digital signals M, C are selected from the next backscan onwards. ，
Digital signals are selected in the order of BK.

When the digital signal Y is selected, the counter section 15 starts counting the printed dots as described above, the toner consumption calculation circuit 16 calculates the toner amount, and the backscan end signal Elsc latches the toner amount in the latch 16b. .

At this time, the contents of the counter section 15 are cleared by the signal output from the latch 16b. Then, latch 16b
A signal TY converted into the amount of replenishment toner latched in is set in the replenishment control section 17.

On the other hand, for image output, document reading scanning (main scanning)
When the image processing section 27 starts, digital signals Y, M, C, and BK are similarly output from the image processing section 27. Then, the second selector 52 selects only one desired digital signal. In this case, since this is the first main scan, the digital signal Y for yellow toner is selected by the main scan start signal R55 and stored in the next stage synchronous memory 53. Digital signals for several lines are stored in the synchronous memory 53, and transferred to the next stage in synchronization with the operation of the color printer 22 by the synchronous memory controller 54, forming a latent image on the photoreceptor 1L. Then, after a predetermined period of time has elapsed, the yellow toner developer 31y starts operating, the yellow toner latent image is visualized, and the third developer 31y is activated by the developing operation signal Ds (shown in FIG. 6(g)). The selector 55 selects the replenishment motor driver 56v for replenishing yellow toner, and drives the replenishment motor 57v with the amount of toner TY calculated from the digital signal Y read during backscanning, thereby replenishing the toner consumed in this development. amount is replenished.

Next, the scanning unit 25 of the color reader 21 starts back scanning and main scanning again, and the same scanning is performed for magenta, magenta,
This is also done for cyan and black toner.

Note that the data read during backscanning ultimately only needs to be density data and is not used for high-definition image reproduction, so the scanning speed is increased and the image signal is sampled at a predetermined period. If you determine the amount of toner by doing this, you can support high-speed printing.

〔Effect of the invention〕

As explained above, the present invention includes a consumption amount calculation means for calculating the consumption amount of developer according to input image information, and a developer corresponding to the developer consumption amount calculated by this consumption amount calculation means. Since the replenishment control means is provided to replenish the developing means in parallel with the development of the developing means, it is possible to replenish the consumed developer detected before the developing step in parallel with the developing step, so that images with stable density can always be obtained. It has the excellent advantage of being able to output continuously.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an image recording apparatus showing an embodiment of the present invention, FIGS. 2(a) to (f) are timing charts explaining the operation of FIG. 1, and FIG. FIG. 4 is a schematic diagram illustrating the color sensor shown in FIG. 3, and FIG. 5 is a schematic cross-sectional view of the full-color image recording system shown in FIG. The control block diagrams in FIGS. 6(a) to 6(g) are timing charts for explaining the operation of FIG. 3. In the figure, 1 is a photoreceptor, 2 is a charger, 3 is an exposure device, 3d is an LED array, 3b is a light converging lens, 4 is a developing device,
4d is a developing roller, 4b is a stirring roller, 5 is a replenishing device,
5a is a supply roller, 5b is a hopper, 6 is a paper feed cassette,
7 is a transfer device, 8 is a cleaning device, 9 is a conveyance device,
1Q is a fixing device, 11 is a paper output tray, 12 is a reader section,
13 is an AND circuit, 14 is a drive circuit, 15 is a counter section, 16 is a toner consumption calculation circuit, 16d is a pulse number output section, 16b is a latch, 17 is a supply paper control section, ]8 is a supply motor. Figure 3

Claims (1)

[Claims] In an image recording apparatus having a developing means for developing an electrostatic latent image formed on a photoconductor with a developer supplied from a replenishing means, a consumption amount for calculating the consumption amount of the developer according to input image information. An image characterized by comprising an amount calculating means and a replenishment control means for replenishing the developing means with developer corresponding to the amount of developer consumed calculated by the consumption calculating means in parallel with the development of the developing means. Recording device.