JP2009134278A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly make image control depending on a toner cartridge. <P>SOLUTION: An image forming apparatus mounted with a toner cartridge having a memory means includes a toner cartridge which stores a plurality of control data depending on toner in the toner cartridge, an acquisition means which selects one of the plurality of control data in the memory means and acquires image formation-related information, and a setting means which sets image formation parameters on the basis of the image formation-related information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image control technique corresponding to toner filled in a toner cartridge.

  Conventionally, as disclosed in Patent Document 1, a method of correcting image forming conditions in consideration of characteristic data of toner recorded in advance on an IC chip provided in a toner cartridge is known.

In order to improve the color reproducibility of a color image, the image forming apparatus forms a specific solid image on a photoconductor and reads the toner density with a sensor. Then, when the toner density is low or the toner density is high, the development contrast is adjusted so as to obtain an appropriate toner density, and the variation in the toner adhesion amount of each color is adjusted. By adjusting the development contrast, the toner adhesion amount of each color can be obtained uniformly, so that the color reproducibility of the color image can be stabilized as compared with the case where the development contrast is not adjusted.
Japanese Patent Laid-Open No. 6-149051

  However, the configuration described in Patent Document 1 described above does not take into consideration that the physical properties of the toner fluctuate depending on the environment and the like, and cannot be said to have appropriately corrected the image forming conditions.

  Even if the toner adhesion amount can be made uniform, when a toner cartridge filled with toner of a different color tone is attached when the toner cartridge is replaced with a new one, even if the toner adhesion amount can be made uniform, There is a problem that the color reproducibility of a color image differs from that before toner replacement.

  Therefore, the present invention provides an image forming apparatus capable of performing appropriate image control according to the toner cartridge.

  (1) An image forming apparatus according to an embodiment of the present invention includes a cartridge that stores a plurality of control data corresponding to toner in a toner cartridge in a storage unit, and one of the plurality of control data from the storage unit. And acquiring means for acquiring information relating to image formation, and setting means for setting image forming parameters based on the information relating to image formation.

  (2) In the image forming apparatus according to (1) according to the embodiment of the present invention, the plurality of control data includes a plurality of data created according to physical properties of the toner.

  (3) In the image forming apparatus according to (2) according to the embodiment of the present invention, the physical property of the toner is a resistance value of the toner.

  (4) In the image forming apparatus according to (2) according to the embodiment of the present invention, the physical property of the toner is a particle diameter of the toner.

  (5) In the image forming apparatus according to (2) according to the embodiment of the present invention, the physical property of the toner is a toner production lot.

  (6) In the image forming apparatus according to (2) according to the embodiment of the present invention, the physical property of the toner is hue information of the toner.

  (7) In the image forming apparatus according to (2) according to the embodiment of the present invention, the setting unit sets a value according to temperature as information relating to the image formation.

  (8) In the image forming apparatus according to (2) according to the embodiment of the present invention, the setting unit sets a value corresponding to humidity as information relating to the image formation.

  (9) In the image forming apparatus according to (2) according to the embodiment of the present invention, the setting unit sets a value corresponding to the number of printed sheets as information relating to the image formation.

  (10) In the image forming apparatus according to (2) according to the embodiment of the present invention, the setting unit sets a value corresponding to a life period as information relating to the image formation.

  (11) In the image forming apparatus according to (7) according to the embodiment of the present invention, the setting unit sets a bias voltage of the charging charger.

  (12) In the image forming apparatus according to (8) according to the embodiment of the present invention, the setting unit sets a bias voltage of the charging charger.

  (13) The image forming apparatus according to (1) according to the embodiment of the invention includes a measuring unit that measures the toner resistance value.

  (14) The image forming apparatus according to (1) according to the embodiment of the present invention includes a measurement unit that measures an environmental condition, and the setting unit responds to the environmental condition based on the control table. Set image formation parameters.

  (15) In the image forming apparatus according to (14) according to the embodiment of the present invention, the measurement unit measures humidity.

  (16) In the image forming apparatus according to (2) according to the embodiment of the present invention, when the image sensor for measuring the toner density is provided, the setting unit adjusts the development contrast.

  (17) In the image forming apparatus according to (2) according to the embodiment of the present invention, the information related to the image formation is material environment characteristic information.

  (18) In the image forming apparatus according to (17) according to the embodiment of the invention, the setting unit sets based on environmental conditions calculated from the material environmental characteristic information and the toner resistance value.

  The image forming apparatus according to this embodiment can perform appropriate image control according to the toner cartridge.

  Hereinafter, the form for implementing is demonstrated.

  FIG. 1 is a perspective view showing an external view of an image forming apparatus 101 according to an embodiment. The image forming apparatus 101 is a quadruple tandem color copier. The image forming apparatus 101 outputs image information as an output image called hard copy or printout, for example, and an arbitrary size paper (output) used for image output to the image forming unit 1 A sheet supply unit 3 capable of supplying a medium), and a scanner 5 that captures image information, which is an object on which an image is formed in the image forming unit 1, as image data from an object holding the image information (hereinafter referred to as a document). When the original is in a sheet form above the image forming unit 1, after the image information is read by the scanner 5, the original that has been read is discharged from the reading position to the discharge position, and the next original is read. An automatic document feeder 7 for guiding the position is provided. In addition, the image forming apparatus 101 is provided with an instruction input unit for instructing the start of image formation in the image forming unit 1 and the start of reading the image information of the original by the scanner 5, that is, the display unit 9 as a control panel. ing.

  FIG. 2 is a schematic view showing the internal structure of the image forming unit 1 as seen from the front side. Toner cartridges 40a, 40b, 40c, and 40d are juxtaposed on the upper side of the image forming unit 1. The toner cartridges 70a, 70b, 70c, and 70d are detachable from the cartridge holding mechanism 60 provided on the front side of the image forming unit 1. The toner cartridges 70a, 70b, 70c, and 70d are for supplying toners of yellow, magenta, cyan, and black.

  The image forming unit 1 includes first to fourth photosensitive drums 11a to 11d that hold latent images, developing devices 13a to 13d that develop latent images formed on the photosensitive drums 11a to 11d, and photosensitive drums 11a to 11a. The transfer belt 15 that holds the developer image developed on the photosensitive drum 11d in a stacked state, the cleaners 16a to 16d that remove the toner remaining on the photosensitive drums 11a to 11d from the individual photosensitive drums 11a to 11d, and the photosensitive drum 11a And charging chargers 17a to 17d for charging 11d.

  The image forming unit 1 converts the developer image laminated on the transfer belt 15 into a sheet-like form such as a general plain paper that is not specially processed or an OHP sheet that is a transparent resin sheet. The image forming apparatus includes a transfer device 18 for transferring to an output medium, a fixing device 19 for fixing the developer image transferred to the output medium to the output medium, and an exposure device 21 for forming latent images on the photosensitive drums 11a to 11d.

  Each of the first to fourth photoconductive drums 11a to 11d is provided by developing devices 13a to 13d containing toners of any color of Y (yellow), M (magenta), C (cyan), and Bk (black). An electrostatic image (latent image) of a color to be visualized (developed) is held, and the order of arrangement is defined in a predetermined order according to the characteristics of the image forming process and toner (developer). The transfer belt 15 holds the developer images of the respective colors formed by the first to fourth photosensitive drums 11a to 11d and the corresponding developing devices 13a to 13d in the order of (developer image formation).

  The paper supply unit 3 supplies an output medium to the transfer device 18 at a predetermined timing when the transfer device 18 transfers the developer image.

  The cassette set in the plurality of cassette slots 31 accommodates an output medium of an arbitrary size. In response to the image forming operation, the pickup roller 33 takes out the output medium. The size of the output medium corresponds to the size of the developer image formed by the image forming unit main body 1. The separation mechanism 35 prevents the pickup roller 33 from taking out two or more output media from the cassette. The plurality of transport rollers 37 transport the output medium limited to one sheet by the separation mechanism 35 toward the aligning roller 39. The aligning roller 39 sends the output medium to a transfer position where the transfer device 18 and the transfer belt 15 are in contact with the timing at which the transfer device 18 transfers the developer image from the transfer belt 15. A plurality of cassette slots 31, pickup rollers 33, and separation mechanisms 35 are prepared as necessary, and the cassettes can be arbitrarily mounted in different slots.

The output image in which the image information is fixed on the output medium via the fixing device 19 is discharged to a discharge tray 51 defined on the side of the scanner 5 and above the image forming unit main body 1. Further, the image forming apparatus 101 has a side discharge tray 59 on the side surface of the image forming unit 1. The output medium discharged from the fixing device 19 is guided to the side discharge tray 59 via the relay conveyance unit 71 connected to the switching unit 55.
FIG. 3 is a block diagram illustrating operations in the toner cartridge 40 a and the image forming apparatus 101. Hereinafter, although the case of the toner cartridge 40a will be described, the same applies to the toner cartridges 40b, 40c, and 40d.

  First, an embodiment of setting image forming parameters for controlling process conditions when the toner cartridge 40a is mounted in the image forming apparatus 101 will be described.

  Here, the process condition control refers to operation control of various apparatuses necessary for actually executing print processing or the like. Specifically, it is control of the bias voltage value applied to the charging charger 17a necessary for charging the photosensitive drum. The process condition control may be operation control for the developing device 13a, the cleaner 16a, the fixing device 19 and the like as well as the charging charger 17a. The image forming parameters are set values relating to operations for the photosensitive drum 11a, the developing device 13a, the cleaner 16a, the charging charger 17a, the fixing device 19 and the like that execute a printing process or the like.

  The toner cartridge 40a is provided with a memory 403. The memory 403 stores collation data and a plurality of control tables described later. For the memory 403, for example, a general-purpose IC chip is used.

The control table includes a plurality of tables in which charging voltage values for the charging charger 17a in printing processing or the like are stored in accordance with the physical properties of the toner accommodated in the cartridge. Instead of the charging voltage value for the charging charger 17a, the developing bias value for the developing device 13a, the toner density (or laser light amount), the peeling output voltage value for the cleaner 16a, the voltage control value for the fixing device 19, and the operation of the photosensitive drum 11a. A setting value such as a value may be defined. The toner physical properties are, for example, the toner charge amount, resistance value, production lot, particle diameter, and the like. In this embodiment, a plurality of control tables are provided according to the characteristics.

  The image forming apparatus 101 includes a CPU 110, a memory 111, a temperature / humidity sensor 112, a transmission / reception unit 114, and a display unit 9.

  The CPU 110 controls each unit in the image forming apparatus 101. The memory 111 records various information. The temperature / humidity sensor 112 is provided at a predetermined location of the image forming apparatus 101 and measures the temperature and humidity in the image forming apparatus 101.

  The transmission / reception unit 114 reads and writes information recorded in the memory 403 provided in the toner cartridge 40a. The transmission / reception unit 114 may be wired communication or wireless communication with the memory 403. The display unit 9 displays various information in response to a request from the CPU 110. The toner density sensor 115 is provided in the vicinity of each of the developing devices 13a to 13d. The toner concentration sensor 115 detects the toner concentration of the toner stored in the developing device 13a. The same applies to the developing devices 13b to 13d.

  FIG. 4 is a flowchart showing information writing to the memory 111 and the memory 403 when setting image forming parameters in the first embodiment.

  First, when it is recognized that the image forming apparatus 101 is powered on or the front cover 1a is opened and closed (Act 100), the CPU 110 executes the following processing. The CPU 110 compares whether or not the collation data A1 stored in the predetermined area of the memory 111 of the image forming apparatus 101 matches the collation data B1 stored in the predetermined area of the toner cartridge memory 403 (Act 101). . In the image forming apparatus, the same code as the verification code B1 acquired in advance from the toner cartridge 40a is stored as A1.

  When the collation data A1 and the collation data B1 do not match (Act 101, NO), the CPU 110 executes a normal printing process without executing the image forming parameter change described in the present embodiment (Act 102). That is, the process condition control in which the value of the image forming parameter is changed is executed only when the image forming apparatus 101 can recognize the inserted toner cartridge 40a.

  When the matching data A1 and the matching data B1 match (Act 101, YES), the CPU 110 selects and reads one of the image forming control table groups stored in the memory 403. Then, the CPU 110 writes the selected control table in the memory 111 (Act 103).

  Here, the CPU 110 selects the control table as follows. Here, an example will be described in which a plurality of control tables are created according to the resistance value of toner.

  In the control table, as shown in FIG. 5, three patterns of toner resistance values of less than 8.0, 8.0 or more and less than 14.0, and 14.0 or more are prepared. CPU 110 selects one control table from these tables. The method of selection is arbitrary. The table to be read may be changed every time depending on the setting of the service person, or the table to be read by default may be determined and changed according to the setting.

  As shown in FIG. 6, each control table is controlled according to the environment (temperature and humidity) or life period, and according to the temperature range and humidity range, the charging charger bias voltages C1, C2, C3,.・ Or, D1, D2, D3 ... or E1, E2, E3 ... are set. Alternatively, in the control table, bias voltages F1, F2, F3,... Of the charging charger may be set according to the number of printed sheets. A plurality of tables may be provided as a set for a certain toner resistance value by combining the environment and life. The three tables shown in FIG. 5 are set to change the bias voltages C1, C2, and C3 of the charging charger according to the humidity range according to the resistance value of the toner.

  Next, the CPU 110 sets the image forming parameters from the selected table using the values calculated from the temperature / humidity sensor 112 and the print number counter 116 provided at predetermined positions of the image forming apparatus 101. That is, the CPU 110 extracts the operation setting value specified by the environmental temperature, the relative humidity, or the number of prints as a variable from the control table, and sets it as an image forming parameter. Then, the CPU 110 executes optimum process condition control (image control) from the set image forming parameters (Act 104). Next, the CPU 110 executes 1-job print processing or the like under optimal process condition control (Act 105).

  In the embodiment described above, the CPU 110 reads the control data from the selected table based on the value detected by the temperature / humidity sensor 112 provided in the image forming apparatus 101, writes the control data in the memory, and refers to this. Optimal process conditions are controlled by changing image forming parameters. A control table based on the count value of the number of printers by the image forming apparatus 101, the usage time of consumables such as developer by the photosensitive drum 11a and the developing apparatus 13a, etc., even if the value is other than temperature and humidity. The optimum process condition control may be performed by changing the image forming parameters with reference to FIG. Further, the process condition control may be performed by optimizing the value related to the voltage control of the fixing device 19 based on the counter value regarding the fixing device 19.

FIG. 7 shows the process condition control when a plurality of control tables are recorded in the memory 403 of the toner cartridge 40a according to the present embodiment and the process when the memory 111 of the image forming apparatus 101 stores a default control table. It is a comparison figure of condition control.

  It has been demonstrated that when a plurality of control tables recorded in the memory 403 of the toner cartridge 40a are used, an appropriate printing process is performed in terms of image density and fog rate.

  As described above, since the toner cartridge 40 a records a control table suitable for the toner cartridge 40 a in the memory 403, the image forming apparatus 101 refers to the control table in the memory 403 to refer to the toner cartridge. It is possible to perform optimum process condition control corresponding to each 40a. Accordingly, the toner cartridge 40a can be used for a long time.

  In the above embodiment, the case of the toner cartridge 40a has been described. However, the present invention can also be applied to consumables such as the photosensitive drum 11a, the fixing device 19, the cleaner 16a, and the developing device 13a using a developer. Further, it is naturally applicable not only to the image forming apparatus 101 but also to a printer.

  Next, a change in image forming parameters according to the second embodiment based on the hue information recorded in the memory 403 when the toner cartridge 40a is attached to the image forming apparatus 101 will be described using the flowchart shown in FIG. .

  Similar to the above, collation data is stored in the memory 403 of the toner cartridge 40a. Also, hue information is recorded. The hue information is information obtained by measuring the color coordinates (L *, a *, b *) of the toner filled in the toner cartridge 40a with X-Lite.

  When the CPU 110 detects that the toner filled in the toner cartridge 40a has run out, it displays “Please replace the toner cartridge 40a” on the display unit 9 (Act 200). The user removes the used toner cartridge 40a from the image forming apparatus 101 and attaches a new toner cartridge 40a to the image forming apparatus 101 (Act 201). When a new toner cartridge 40a is attached to the image forming apparatus 101, the CPU 110 collates the information in the memory 111 of the image forming apparatus 101 with the information in the memory 403 of the toner cartridge 40a. (Act 202).

  When the memory 403 is not provided in the toner cartridge 40a or when the collation data cannot be read (Act 202, NO), the CPU 110 does not change the image forming parameter based on the hue information, and does not change the toner to the developing device 13a. And the display unit 9 displays that the toner is being replenished (A203). Only when the collation can be confirmed, the change of the image forming parameter based on the hue information is effective.

  If the collation has been confirmed, the CPU 110 reads out the hue information recorded in the memory 403 (Act 204) and changes the image formation parameter (Act 205). The image forming parameters before the change are recorded in the memory 111 of the image forming apparatus 101. When the CPU 110 recognizes that the image sensor 22a is provided in the image forming apparatus 101 as shown in FIG. 9 after changing the image forming processing parameters reflecting the hue information (Act 207, YES), the developing device 13a sets the toner. Is supplied (Act 209). The image sensor 22a is located on the lower surface side of the transfer belt 15, and detects the toner density of the electrostatic image on the photosensitive drum 11a. Similarly, image sensors are provided for the developing devices 13b, 13c, and 13d.

  When the developing device 13a completes the toner replenishment, the CPU 110 activates the image sensor 22a to acquire the toner density. Then, the CPU 110 adjusts the development contrast in the developing device 13a based on the acquired toner density (Act 209).

  When the adjustment of the development contrast is completed, the CPU 110 displays on the display unit 9 that printing is possible (Act 210).

  As shown in FIG. 10, when the image sensor 22a is not provided in the image forming apparatus 101 (Act 207, NO), the CPU 110 changes the image forming parameter to reflect the hue information, and then the developing device 13 supplies toner. Is started (Act 207).

  With the above configuration, even when the toner cartridge 40a is replaced, the image forming apparatus 101 reads the hue information of the toner filled in the toner cartridge 40a and changes the image forming parameters based on the hue information. Reproducibility can be realized. Of course, the hue information may be stored in a plurality of control tables in accordance with the physical properties of the toner, and one may be selected from this control table, as in the first embodiment.

  Next, a third embodiment will be described with reference to a block diagram of operations in the toner cartridge 40a and the image forming apparatus 101 shown in FIG.

  The memory 403 of the toner cartridge 40a records material characteristic information and resistance change element characteristic information.

  The material characteristic information is information indicating a change in toner characteristics (for example, charge amount, toner fluidity, toner resistance value, etc.) in accordance with an environmental state (for example, absolute humidity inside the image forming apparatus 101). The variable resistance element characteristic information is, for example, information that associates the toner resistance value with the absolute humidity from 20% to 85% or characteristic curve information that converts the absolute humidity from the toner resistance value.

  First, when the toner cartridge 40a is attached to the image forming apparatus 101, the CPU 110 acquires collation data from the memory 403 of the toner cartridge 40a. The CPU 110 compares with the collation data stored on the main body side and determines whether or not the desired toner cartridge 40a is mounted.

  If the CPU 110 does not determine that the desired toner cartridge 40a is mounted, the material characteristics of the toner filled in the toner cartridge 40a are unknown, and the following image forming parameter setting is not executed. Then, the CPU 110 controls the display unit 9 to display that the toner cartridge 40a is not attached.

  When the CPU 110 determines that the desired toner cartridge 40a is mounted based on the collation data, the CPU 110 acquires material characteristic and resistance change element characteristic information from the memory 403 of the toner cartridge 40a. Here, the toner resistance value measurement unit 113 is connected in series with a resistance change element 1131 and a resistance change element 1131 whose electric resistance value changes according to environmental conditions such as temperature and humidity, and the resistance element whose electric resistance value does not change according to the environment. 1132, a resistance element 1132, and a resistance change element 1131, a power source 1133 that applies a voltage of 5 V or 12 V, for example, and an OP amplifier 1134 that reads the value of the voltage across the resistance change element 1131. The CPU 110 can calculate a toner resistance value that is a resistance value of the resistance change element 1131 that varies from the value of the voltage across the resistance change element 1131 read by the OP amplifier 1134. The toner resistance value measuring unit 113 measures the voltage value of the resistance change element read by the OP amplifier 1134 and also measures the toner resistance value that is the value of the resistance change element. The CPU 110 acquires the environmental condition by comparing the toner resistance value measured by the toner resistance value measurement unit 113 with the resistance change element characteristic information acquired from the memory 403 of the toner cartridge 40a.

  Here, the resistance change element may be provided in the toner resistance value measurement unit 113 of the image forming apparatus 101 or may be provided in the toner cartridge 40a.

  Then, the CPU 110 acquires image forming parameters stored in the memory 111. The CPU 110 changes the image forming parameter defined according to the environmental condition and the material characteristic to the optimum value corresponding to the environmental condition and the material characteristic information acquired from the memory 403 of the toner cartridge 40a. The image forming parameter information includes voltage control values for the developing device 13a, the cleaner 16a, the charging charger 17a, the fixing device 19, and the charge amount of the photosensitive drum 11a in the printing process or the like for each toner material characteristic that changes according to the environmental conditions. , Parameter data in which physical property values such as development bias, toner density (or laser light quantity), particle size distribution, and thermal characteristics are set. The CPU 110 sets the optimal image forming parameters corresponding to the material characteristics and environmental conditions in each unit and executes the printing process.

  With the above-described configuration, the image forming apparatus 101 according to the present exemplary embodiment can increase the size of the apparatus and set delays in image forming parameters for printing processing according to the characteristics specific to the toner filled in the toner cartridge 40a. It can be set without it. In other words, even if the toner cartridge 40a has a constant quality, the quality of the filled toner varies, and the toner cartridge 40a filled with a low-quality and low-quality toner is mounted on the image forming apparatus 101. Even in this case, the image forming apparatus 101 can perform an optimum printing process according to the material characteristics and environmental conditions unique to the toner.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a schematic diagram illustrating an appearance of an image forming apparatus to which a toner cartridge according to a first embodiment is applied. FIG. 2 is a schematic view illustrating the internal structure of the image forming apparatus according to the first embodiment as viewed from the front side. FIG. 5 is a block diagram illustrating operations in the image forming apparatus and the toner cartridge according to the first embodiment. 4 is a flowchart illustrating information writing when setting image forming parameters in the image forming apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a control table used for setting the image forming apparatus according to the first embodiment. It is a figure which shows the image formation parameter in the image forming apparatus which concerns on 1st Embodiment. FIG. 5 is a diagram illustrating a comparison of print processing when an image forming parameter is set and when it is not set in the image forming apparatus according to the first embodiment. 10 is a flowchart illustrating setting of image forming parameters using hue information in the image forming apparatus according to the second embodiment. It is a figure which shows the image sensor provided in the image forming apparatus which concerns on 2nd Embodiment. FIG. 10 is a block diagram illustrating operations in an image forming apparatus and a toner cartridge according to a third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming part, 9 ... Display part, 22a ... Image sensor, 40a ... Toner cartridge, 101 ... Image forming apparatus, 110 ... CPU, 111 ... Memory, 112 ... Temperature / humidity sensor, 113 ... Toner resistance value measuring part, 114 ... transmission / reception unit 115 ... toner density sensor 116 ... printing sheet counter 403 ... memory

Claims (6)

A toner cartridge having storage means, and storing a plurality of control data corresponding to the toner in the toner cartridge in the storage means;
An acquisition unit that selects one of the plurality of control data from the storage unit and acquires information relating to image formation;
Setting means for setting image forming parameters based on the information relating to the image formation;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the plurality of control data includes a plurality of data created according to physical properties of the toner.   3. The image forming apparatus according to claim 2, wherein the physical property of the toner is a resistance value of the toner.   The image forming apparatus according to claim 2, wherein the setting unit sets a value corresponding to a temperature as information relating to the image formation.   The image forming apparatus according to claim 1, further comprising a measuring unit that measures an environmental condition, wherein the setting unit sets an image forming parameter corresponding to the environmental condition based on the control table.   The image forming apparatus according to claim 2, wherein when the image sensor for measuring the toner density is provided, the setting unit adjusts the development contrast.

Images